Number cakes are layer cakes that are shaped like a number. This tutorial here shows you how to make a two layer number cake that you can decorate with flowers, cookies, and candies. One cake will serve about 6-9 people; two about 12-18.
As a home baker, I didn't find any purpose in buying a special number pan that I'd probably only use once. My number cakes can be made using printable paper templates (located at the bottom of this post).
All you have to do is print out the number you need, cut them out, and then place them directly on sheets of cake. Use a small paring knife to trace around the number. Your cakes are now ready to fill, stack, and decorate.
If you're trying to make a letter cake, check out my post here, which contains the instructions and letter templates.
If you want to watch how I put a number cake together, here's a video tutorial on a lemon blueberry "2" cake.
To make this cake, you're going to need a cake baked in a half sheet pan. The tutorial above shows you how to do exactly that and you can bake most cake recipes this way. (I say "most" because it's hard to do angel food cakes and probably European style cakes such as genoise, so try to stick with butter/oil cakes leavened with baking powder/baking soda. Or you can just use any cake in my Cakeculator, here.)
You can use almost any frosting to fill and top this cake. It will largely depend on your preferences and how you plan to store the cake. The buttercreams listed in my Cakeculator (Swiss meringue, condensed milk, etc.) will be the most stable. That means they'll easily hold up the cake and heavy toppings if you like.
If you prefer lighter frostings such as whipped creams, you'll have to chill the cake, which will also help with stability. You'll probably want to stabilize the whipped cream in some sort of way and I have a whole video on different methods. Any of them should work fine to stabilize the whipped cream enough to hold up the second layer as well as decorations. (see video on whipped cream stabilizers here.)
As for the decorations - I've seen cookies (macarons are popular), fruit, flowers, and all types of candy. If there's a theme or flavor that you're aiming for, this is the area where you can be really creative.
It will depend on the number that you choose. For instance a number "1" is going to have less servings than an "8". If you look at the number "2" I did in the lemon blueberry cake video above, that cake should give around 8-10 servings of cake. Generally speaking though, I think serving 6-9 adults with one number is a safe bet.
If you have extra ingredients on top, like cookies or more fruit, you may be able to serve more people with smaller (but more substantial) slices.
Number cakes are what I would classify as a naked cake. By that I mean that the sides are completely exposed. Naked cakes have a special consideration in that because the cake is continually exposed to air, you run the risk of a drying out the cake.
So dry cakes are typically caused by a couple things - starch retrogradation (which I will get into the science of in another post) and moisture loss, which is what I'll address right now.
Theres a couple things I do to prevent moisture loss. The easiest thing is that I usually make these cakes the day that I'm going to serve them. Even if I bake the sheet cakes the day before, they are wrapped in plastic and saved on my counter top. Then the day I need it, I cut, fill, stack, and decorate.
I know that's not always possible, so you can try using a simple syrup. Heat equal parts sugar and water until it comes to a boil and all the sugar has dissolved. You can add extracts or other flavorings, but that's a general way to make a syrup. Then, during assembly, you can brush the syrup onto your cakes.
No need to buy special paper or tape pieces together.
These templates are in .pdf format, and when you click on the link a new window will popup with the template.
When the print prompt comes up make sure that you select "actual size" and not "fit". This means that the size of the letter will print the size that I designed it, which takes up an entire 8.5x11" sheet of paper.
You will notice that some of the lines along the edges do not print. This is normal because not all printers are able to print so closely to the edge. I've designed the letters to get the maximum size for one sheet of paper, so just consider that missing line the "edge".
You can print directly from your browser or download and save to print for later. You'll need a pdf reader for that. Some popular ones include Preview on Mac, or you can download Adobe Acrobat Reader DC for free on most devices.