Ermine buttercream is a type of cake frosting that goes by many names, including boiled milk, cooked flour, heritage, or Ermine frosting. The texture and flavor of this frosting are unlike any other buttercream I've tested. It's light and fluffy with a very mild sweetness and buttery flavor. Interestingly, although it seems lighter, it is also one of the strongest in terms of temperature and pressure stability, which I'll cover in full detail down below.
The name "Ermine" is a type of weasel and it's thought the name of this frosting came from its likeness to the softness and velvety texture of an ermine's fur. Traditionally, this type of frosting is used for red velvet cake. The milder flavor and texture make it versatile and great for those who want something a little lighter.
The process of making this buttercream is two steps. The first is a cooking step, whereby a flour paste is made by combining milk, flour, and sugar in a pan. When left to cool, this creates a thickened white mixture with a pudding-like consistency. (This is not a roux, which is technically flour cooked in fat, such as butter, and a base for many types of sauces and gravies.)
The second step is combining the flour paste with softened butter. The final buttercream is slightly off-white, aerated, fluffy, and absolutely delicious.
If you're used to eating buttercreams such as American, Swiss meringue, Russian, etc., this frosting will seem much lighter in texture and buttery flavor.
This is because you need less butter to bring this buttercream together than all the other kinds. Let me show you.
Here is a summary chart outlining the relative butter and sugar content.
These percentages are the levels of sugar and butter used in my classic buttercream recipes. You may not see the butter and sugar add up to 100% because other ingredients often bring the total recipe up to 100.
Using just the butter and sugar levels is incredibly useful. Butteriness and sweetness are two important characteristics in frostings. Not only will these two numbers give you an indication of the buttercream's overall taste but also its texture.
For example, my American Dreamy Buttercream is about 50% sugar and 50% butter. So that frosting is going to be buttery and sweet.
Now compare that two Ermine buttercream with about 25% sugar and 30% butter. This frosting is going to be less sweet and less buttery. Also, because of the lower amount of butter than all the other buttercreams, it will be lighter in texture.
The other ingredients (flour and milk) also play a big part in contributing to the lighter texture of this buttercream. But that will make more sense in a bit when I cover the stability of this frosting.
This frosting has a very unique flavor. I have tasted all the buttercreams in the chart above and many others, and it is truly unlike any of them. Although it's classified as a buttercream (i.e., a frosting with butter as the primary fat and emulsifier), it tastes the least of butter.
The flavor has a bright vanilla and milky-dairy flavor with the slightest taste of butter at the end. Some describe it as similar to whipped cream. This is reasonably accurate - whipped cream is well, cream, and this frosting has a large proportion of butter and milk. We're likely tasting all those dairy proteins and fats, giving it that milky flavor. Starch (flour) mitigates this a little because it offers bulk and dilutes the milky flavor. However, it's still the most predominant flavor in my opinion.
My family does not enjoy most classic buttercreams and doesn't like the heaviness or butteriness in large amounts. I do - but I'm pretty much alone in that regard. I made them this buttercream, however, and they absolutely loved it.
So, this is one to try if you're looking for buttercream with the least amount of butter flavor and heaviness.
Ermine is surprisingly stable. And when I say that, I'm talking about pressure stability (how well it holds as a cake filling) and temperature stability (high heat and humidity.)
To test frostings, I try to use the frosting in as many different scenarios as possible to give you the most accurate idea of what it would be to work with it. Below I'll go through four tests and rank the outcomes numerically, with 1 being the worst performing and 5 being the best performing.
The first test is the easiest, and most frostings do relatively well. There are no external pressures on the frosting when piped other than gravity, so what I'm really looking for is the sharpness of piped shapes using a star piping tip.
It pipes wonderfully and has an excellent smooth feel when it comes out of the tip, which translates to lovely sharp designs. For this, Ermine frosting got a 5/5.
For this test, I apply a good amount of the frosting on the outside of a 2 layer cake and then attempt to smooth it using a cake scraper. What I'm looking for is the ability to get a smooth surface on the cylindrical shape of the cake. I take a look at the air bubbles and the finished texture.
I'll preface this by saying I'm still learning as a cake decorator, so it may be my technique. But I found this frosting challenging to get smooth on the sides. The frosting is more aerated than what I'm used to, and that likely has to do with the lower amount of butter in the recipe (see the chart above.) The more butter you have, the more fat, and fat smooths and glides very easily.
Another reason I think it was hard to get smooth is the starch granules. When starches (such as flour, corn starch, and even cocoa powder) are heated and swell with water, they form an elastic or gel-like quality. I believe these starch granules formed a type of glue inside the buttercream. If you try to imagine smoothing out a thick glue into a smooth surface - that will be more difficult than a smooth and shiny fat, such as butter.
Potentially more butter could remedy this, but overall, I give this frosting a 2/5 in the smoothing category.
For this test, I'm looking at structural stability. I placed about 1 1/4 cups of frosting between two layers of 6 inch cake. I then put a 2 lb weight atop the cake to simulate weight from extra cake layers and left it at room temperature for 2 hours. I'm looking for any frosting squeezing out or if there's any curvature on the outer frosting coat.
This cake did not budge. It was the same from when I finished the cake, throughout all the pressure testing, and even afterward. I had to stop filming and leave this cake out. Even 24 hours later, this cake was fully intact, with no frosting bulging out from the middle and no perceivable change in the outside layer of frosting.
So you know the starch glue I was talking about in the previous test for smoothing? Although it proved difficult to smooth, I think it provides a structural component for this frosting.
Buttercreams are made predominantly of butterfat, which, if you press on it hard enough, will yield to pressure and stay that way. Now think about something made with starch in it…like the filling of a lemon meringue pie. That's made with cornstarch typically, but if you press on it, it has this resiliency that bounces back. That's the gel that forms with cooked starches. That's on the inside of this frosting! I think it creates a web or gel-like matrix inside the buttercream, giving it more structure and the ability to withstand the weight.
For these reasons, Ermine frosting did the best in my pressure tests and got a 5/5.
For this set of tests, I set up a new terrarium to control heat and humidity.
This allows me to view the effects of different temperatures on frostings. For this set of tests, I used frosted cupcakes. There are no other external pressures, such as additional cake layers from a larger cake. Still, perhaps I'll test that in the future. I left a set of cupcakes frosted with eight buttercreams in two different temps for 2 hours. The first test was at 85F/29C with 78% humidity. The second test was at 90F/32C with 74% humidity.
Ermine frosting was a front runner for high heat and humidity tests. It survived both high temps and humidty tests with just a slight deflation but otherwise kept its piped shape on top of a cupcake. Below are the results of the first test:
Given these results, I give Ermine a 5 out of 5 ranking for my temperature tests.
BTW, here are the heating results of the all the buttercreams I've tested:
If you're interested in seeing my whole video with all the buttercreams, that's right here:
I think most underestimate the strength of Ermine frosting. The key to its power lies in the large portion of starches used. This creates a gel inside the buttercream that helps the stability department. There's no wonder many bakers from the South trust for their red velvet cakes. Not only is it more traditional, but it can also withstand that hotter and humid climate.
Are you ready to make Ermine? Here are the details.
Milk is the primary liquid ingredient for this frosting. You can use any fat percentage because the main function of milk is its water content, which allows the starch granules to swell. You can most likely use other liquids, but the flavor will lean towards whatever you choose (e.g., almond milk will give a slight earthy almond taste.)
Flour is a thickening starch for the cooked pudding. You can use any type of flour, but I use all-purpose wheat flour. Since we're cooking the flour for its thickening properties for the pudding, we don't really care about the gluten content. In this case, the type of flour shouldn't really matter. If you are gluten-free, you'll want to consult a gluten-free conversion chart to add the correct amount to sub in for the wheat-based flour. (I have not tested this myself yet.)
White granulated sugar is the sole source of sweetener for this recipe. Adding it to the cooking step allows it to dissolve within the water contained in the milk. This creates a smooth texture, and you'll also see the pudding instantly turn more glossy after adding sugar. (That's it dissolving into the water contained in the milk.)
Unsalted butter is the primary fat for this buttercream and is added at the end of this process. I use unsalted butter for all my buttercreams because it allows us to flavor the frosting at the end of the process. Salt content varies between butter brands, so this will enable you to customize by taste at the end.
Vanilla and salt are the flavorings for this buttercream. You can sub out the vanilla extract to make a frosting flavor of your choice.
In a shallow pan, pour in the milk and flour. Cook on medium heat while whisking until thickened (1a).
Whisk in white sugar and continue cooking until you see the first bubble pop, then continue to cook for 1 minute longer (1b).
Pour the hot cooked flour mixture into a container. A pie pan or other shallow container is best, and I like to use a sheet pan (2a). Cover with plastic wrap to prevent dehydration and skin forming and cool completely to the touch for at least 30 minutes (2b). The flour paste will be thick like pudding but will thicken slightly as it cools.
Once the flour mixture has cooled, whip the softened butter with the whisk attachment. (3a) until it is lighter in color and texture, at least 2-3 minutes on high speed (3b).
Here is what the cooled flour paste should look like: thickened but definitely still able to fall off the end of the spatula like a super thick cake batter (4a). Add the flour paste to the whipped butter, and using the whisk attachment, whisk on low speed until all the paste has been added (4b). After that, whisk on high speed until it comes together and thickens slightly as the butter takes in the flour paste, 1-5 minutes.
When properly mixed, Ermine should look like this:
Off-white to cream, very fluffy and soft, and air pockets from the whisk (5a). Don't worry about the softness - you can still frost with it. It will seem counterintuitive if you've worked with other buttercreams. Remember, this one has less butter, so it will feel less dense. The texture will feel right in between that of buttercream and whipped cream.
Now switch to a paddle attachment to smooth it out since the whisk incorporates many air pockets. You can flavor it with vanilla and salt here, and add the tiniest speck of purple food coloring if you want a whiter buttercream (5b).
I have yet to try and freeze this buttercream, but I have placed it in the fridge after making it. To bring it back to the consistency for frosting, you'll want to allow the frosting to sit out until it's slightly softened, then add it to the mixer. Use the whisk to bring it back together, and then the paddle to remove the air pockets, as in step 5, from above.
As for cakes and cupcakes that are already frosted, I'm comfortable with leaving these out for a day at room temperature. After that, I will place it in the fridge for longer-term storage.
*You can use any type of flour, but I use all-purpose wheat flour. Since we're cooking the flour for its thickening properties for the pudding, we don't really care about the gluten content. In this case, the type of flour shouldn't really matter. If you are gluten-free, you'll want to consult a gluten-free conversion chart to add the correct amount to sub in for the wheat-based flour. (This is on my list for future testing, so a gluten-free option should be coming soon.)