Chocolate Indulgence Cake Layers:

1. Preheat the oven .
   Move your rack to the middle position. Preheat the oven to 350°F (176°C).
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2. Prepare the cocoa powder syrup.
   In a large heat-proof measuring cup or medium bowl, whisk the cocoa powder, boiling water, and oil until smooth and lump-free. Let it sit for 5–10 minutes to allow the chocolate flavor to bloom.
   
   While the cocoa powder syrup sits, I like to prep other components of the recipe:
   
   1. The pans:
      Line the bottom of two 8-inch (and 2 inches tall) round cake pans with a circle of parchment paper. Do not spray or add any fat to the interior of the pan. You’ll get the best height by leaving them bare.
   2. The eggs:
      This recipe uses eight yolks but only four whites, so I separate them now and reserve the extra four whites for another purpose. The reason I recommend that your eggs be cold from the fridge is that they will be easier to separate, as the fat in the yolk is slightly firmer and easier to detach from the whites.
      
      Additionally, eggs vary in total size and even within the distribution of yolk and white. (I don’t know what’s been going on, but I’ve been getting more “twin yolks” than I ever have in my entire baking life.) Try to go by weight to ensure you get 160 grams of yolks and 120 grams of white. 
   3. Sift the dry ingredients.
      In a large bowl, sift the flour and baking powder. Whisk in the salt and brown sugar. Little soft lumps of brown sugar are ok, but feel with your fingers to ensure there aren’t any of those really hard lumps that sometimes come with brown sugar. Set this bowl aside for now.

By now, your cocoa syrup is ready. Add the eight egg yolks and vanilla extract to the syrup and whisk until fully combined. 

3. Mix the wet and dry mixtures.
   Make a well in the middle of the flour mixture, and slowly pour in the cocoa powder syrup, whisking the entire time to avoid lumps. Set that aside for now while you make the meringue.
4. Make the meringue.
   Add the white sugar to a small bowl so it’s easy to add to the meringue while it whips. In a clean bowl, add the egg whites and beat on medium-high speed until thick and foamy. Gradually add the sugar, waiting 5–10 seconds between additions. Beat until stiff, glossy peaks form.
5. Fold egg whites into the batter.
   Add about ⅓ of the meringue to the chocolate cake batter. Gently fold the mixture until it is well combined, and repeat with the remaining meringue. The final batter should be smooth and airy.
6. Add the batter to the pans.
   Evenly distribute and pour the batter between the two pans. If you want to use a scale, the amount is approximately 870 grams of batter per pan.
7. Bake for 45-50 minutes.
   These are big and moist cakes. You’ll need to bake both cakes for around 45-50 minutes.
   
   The cakes may rise above the rim of the baking pan. You’re going to think I’m crazy, but it will be fine. The cakes dome up during the last third of the baking time, then, during the last 10 minutes or so, the dome will slightly flatten. You’ll know it’s done when the center no longer jiggles and a toothpick comes out clean. When pressed, you should feel some resistance and possibly a slight crackling. Also, you will see some hairline cracks along the surface of the cake. This is normal.
   
   The best way to know when it’s done is to insert an instant-read thermometer in the direct center of the cake, which should read 190°F (88°C).
8. Allow to cool upright in the pan for a short time.
   As the cake cools, it will shrink down to the level of the pan. It will also pull away from the sides, and it may even dip slightly. This is also normal. While the pan is still warm - about 5-10 minutes later, I slide a knife around the perimeter to loosen the cake from the pan and carefully invert it onto a rack or plastic wrap.
   
   If you plan on using it immediately, you can let it cool before frosting. For use the next day, wrap in plastic and leave on the countertop.
   
   In cases where I won’t work with the cake for more than 24 hours, I will wrap the cake and place it in the freezer. Just make sure you lay it on a flat surface to freeze so the cake isn’t malformed/dented. 

Miso Caramel Sauce: 

1. Make the miso-cream.
   Add the miso paste to a small bowl. Warm the heavy cream in a large heatproof measuring cup using the microwave (or a small saucepan) until it is just warm. Splash a bit of the warm cream on the miso paste. Use a small whisk or spatula to whisk the mixture until it is smooth and free of lumps. Then, pour the mixture back into the larger heatproof measuring cup and mix until everything is well combined.
   
   Place the cup aside so you have easy access to it while cooking in the next step.
2. Melt the sugar.
   Add half the sugar to a heavy-bottomed saucepan, along with the lemon juice (or vinegar). Rub into the sugar until it’s no longer clumpy.
   
   Cook over medium heat, stirring constantly with either a wooden spoon or a heat-proof silicone spatula. The sugar will first appear clear and wet, and then start to turn amber in certain areas. Once you get a point where about 90% of the sugar is melted, pour a couple tablespoons of the remaining sugar over the surface. The sugar granules should melt into the amber liquid as you stir. Continue this process until all the sugar is added and has melted into a deep amber color.  (The darker you get, the more bitter the caramel, so I aim for a dark amber/honey color.)
   
   Immediately remove the saucepan from your heat source. 

3. Carefully add the miso-cream to the melted sugar.
   The caramel is very hot, and your heavy cream will immediately release steam upon contact, so be very careful. Add about ¼ cup of the miso cream, stirring constantly until all the cream has mixed into the sugar. Repeat this until all the cream has been added.
   
   If you notice that the caramel starts to ball up uncontrollably, don’t worry, that just means the sugar is beginning to harden, but it’s easily fixable. Just place the saucepan back on the heat source until the sauce is all melted, then remove it from the heat and continue adding the cream.
4. Add the butter.
   Add the sliced butter and continually stir until it’s completely mixed in.
   
   CAREFULLY give the caramel a taste. It should be sweet at first, with a slight hit of the salty, umami-rich miso near the end. I’ve found that the saltiness increases as the caramel cools, so don’t worry if it feels a tad undersalted. However, if you think it’s really undersalted, add a pinch of fine sea salt here to taste. 
5. Store in a glass container.
   Carefully pour the hot caramel into a glass container for storage. When handling the glass, wear gloves or use a kitchen towel as the caramel is still very hot. Allow to cool completely before using. I store my jars of caramel in the fridge. They last at least a few weeks, but honestly, they’ve not been around long enough for me to know their total storage limit :)

For the Chocolate Russian Buttercream:

1. Mix the cocoa paste.
   In a small bowl, add the cocoa powder. Pour in the boiling water and stir until all the lumps have disappeared, forming a thick paste. Set aside. 
2. Prepare the Frosting Butter.
   Add the slightly softened butter to the mixing bowl and whisk on high speed for about 2 minutes, scraping down the sides at least once. After mixing, the butter will be lighter in color, smooth, soft, and ball inside the whisk.
   
   Add the powdered sugar, vanilla extract, and a small pinch of salt to the butter, and whisk again on medium-high speed for another 1-2 minutes.  
3. Add the sweetened condensed milk.
   Continue with the whisk attachment and add the condensed milk in three parts, mixing for one minute on high speed before adding the next portion. Scrape the bowl down a few times during this process.
   
   Once all the milk has been added, mix on high speed for one minute. Just looking at the mixture to see if it’s properly mixed is difficult because the butter and milk are similar colors, so this ensures proper emulsification and prevents a runny frosting. At the end of this step, the buttercream should have a thick and creamy texture.
   
   If your buttercream looks runny, greasy, curdled, or broken at any point during this process, it has not yet been emulsified. Turn up the speed or mix for longer until the elements come together.
4. Add the cocoa paste.
   Scrape in all of your cooled cocoa powder paste and continue mixing with the whisk attachment on medium-high speed until the mixture is completely combined, about 2-3 minutes.‍
5. Flavor and smooth the frosting.
   The whisk attachment introduced lots of air pockets, so switch over to the paddle attachment and mix on low speed for at least a few minutes to smooth out the frosting. Give the frosting a taste.
   
   Add another splash of vanilla if you like. Don’t be shy with the salt; it pairs extremely well with chocolate, so add another pinch if the frosting tastes flat. Properly seasoned, this frosting should taste like a good-quality chocolate ice cream.
   
   If the frosting sits out in the bowl, it may look airy or full of bubbles. This is likely due to the alkalizing agent used in Dutch-processed cocoa interacting with the acidity in the final buttercream. Don't worry; this is a normal occurrence. Simply mix on low speed to remove air bubbles before use.

Vanilla American Dreamy Buttercream:

1. Prepare the Frosting Butter.
   Add the slightly softened butter to the bowl of the stand mixer. With the whisk attachment, mix on high speed for about 2 minutes, scraping down the sides at least once. After mixing, the butter will be lighter in color, smooth, soft, and will form a ball inside the whisk.
   
   Add the powdered sugar (1), vanilla extract, and a small pinch of salt to the butter and whisk again at medium-high speed for another 1-2 minutes. ‍
2. Add the sugar syrup incrementally.
   Add the syrup in 3 to 4 additions. Stop the mixer, then add a small amount and mix at medium speed using the whisk attachment. Repeat until all the syrup is incorporated, scraping down the bowl a couple of times for even mixing.
   
   Mix at high speed for one minute after adding all the syrup. Since most syrups are clear, it can be challenging to determine when they're fully emulsified. To ensure accuracy, set a timer and mix for the full minute.‍
3. Adjust frosting for sweetness and density.
   Taste the frosting to determine how much powdered sugar to add. It should be smooth, creamy, buttery, and slightly sweet. Add powdered sugar in a few increments, mixing at low speed to minimize mess. Once all the sugar is added, mix on high speed for 30 seconds and taste again. I prefer a slightly sweeter buttercream (see my footnotes).
   
   You can stop here or add more powdered sugar as desired. Please note that exceeding twice the amount of powdered sugar (2) may result in a grainy texture due to the presence of sugar granules.
4. ‍Adjust frosting for texture and flavor.
   ‍Switch to the paddle attachment and smooth the frosting at low speed for a few minutes to remove large air pockets. Taste the frosting; if it's too buttery, add heavy cream one tablespoon at a time until the desired consistency is reached. Adjust the salt and vanilla as needed if you’re satisfied with the texture and flavor. Then, whip on low speed for at least one minute.

ASSEMBLY

1. Cut the cake layers.
   We will need eight thin layers of cake, approximately ½ inch in height. Each cake should rise around 1.75-2 inches in your cake pans. This means that each cake layer should be cut 3 times to yield 4 ½-inch layers of cake.
   
   Use a cake leveler or a large serrated knife to slice straight through the layers. My cake leveler has markings on it, so I know how to cut ½ inch slices, but you may need a ruler if you’re using a knife. 
2. Set up the cake board and the first slice of cake.
   Place a cake board onto your cake turner or a cake stand. You can also do this on a large, flat plate or platter, but the outside will be difficult to smooth out, so you may opt for a more rustic look for the outer frosting. We’ll get to that in a bit.
   
   Add a schmear of frosting to the cake board to anchor the cake. Add the first layer of cake.
   
   👉🏻 TIP: Try to use the flattest pieces of cake for the bottom and top - it will help level the cake overall with a sturdy bottom. It’s much easier to deal with uneven cake slices in the middle with more buttercream.
3. Add the chocolate buttercream frosting and miso caramel filling.
   🧁 NOTE: For my cake pictured above, I used chocolate Russian Buttercream to fill and crumb coat the cake, and Vanilla American Dreamy Buttercream for the top coat. You can use either buttercream to do both; simply disregard my labels for the frosting flavors and proceed through these instructions with one type of frosting. However, you can only do this if you’ve prepared enough frosting of one kind, about 7-8 cups.
   
   I use a metal scoop to ensure the same amount of chocolate frosting is evenly distributed between the cake layers. My ice cream scoop holds 3 tablespoons per scoop, and I use three scoops, which equals 9 tablespoons, or ½ cup plus 1 tablespoon, of frosting for each filling application. You can also use a ½ cup measuring scoop and add a slightly heaping scoop of frosting in between each layer.
   
   Use a flat cake spatula to spread frosting evenly to the edges of the cake layer. Create a shallow indentation to hold the miso caramel, leaving a 1-inch border along the perimeter of the cake to create a dam, so the miso caramel doesn’t leak out.
   
   Add approximately 3 tablespoons of miso caramel to the indentation and use a cake spatula to spread it into an even, thin layer.
4. Continue adding cake, chocolate frosting, and filling.
   Add another layer of cake. Get to eye level and ensure that the sides are lining up as even as possible. Use the palm of your hand to apply gentle pressure. This will ensure there are no air gaps in the frosting. Repeat step 3. Continue until all the cake layers have been used up, saving the flattest layer for the very top.
   
   Give your cake a final eye-level look. Adjust the cake if necessary to get straight sides.
5. Spackle in the sides with more chocolate buttercream.
   Apply a crumb coat.
   Now, apply a super-thin layer of frosting (using the chocolate buttercream) to the top and outside of the cake.
   
   There will likely be gaps of frosting, so I like to go in with more chocolate buttercream on the sides to fill all the gaps until it’s level with the side of the cake.
   During this process, my cake takes on a semi-cylindrical shape, but it's quite unappealing in terms of appearance. But it’s ok! The goal here is just to apply a layer of fat in which excess crumbs will get trapped, so that when we do a final coat, it’s free from any chocolate crumbs.
   
   Chill the cake for at least 30 minutes to set the crumb coat. To test, touch the buttercream; it should be firm and not leave any indentations.
6. Apply a top coat of frosting with Vanilla American Buttercream.
   Apply a couple of big dollops of frosting to the top of the cake. Use a flat spatula to spread the mixture evenly over the top, then smooth it out to create a flat surface. I like to leave a slight “ledge” on the top of the cake to keep the caramel on the top.
   
   Apply frosting around the sides and use a bench scraper to create flat and smooth sides.
   Once you like the look of the cake, place it in the fridge while you prepare the decorations.
7. Decorate with fresh flowers, caramel, and/or piping.
   Ensure your caramel is at pouring consistency. You can place the jar in the microwave for about 10-20 seconds to liquefy it further. You don’t want it hot, but just warm enough to run down the side of the cake and smooth along the top.
   
   If you want to do the drip effect like on my cake, pour a few tablespoons of runny caramel into a piping bag and snip off a tiny piece of the bag at the pointed end. Start at the edge of the cake and allow the caramel to run down the sides. Continue moving along the perimeter until you achieve the desired look.
   
   Pour the remaining caramel on top of the cake, inside the ledge you created earlier.
   
   Decorate with fresh flowers.