From America's Test Kitchen Season 6: Old-Fashioned Birthday Cake
**In the video, we mistakenly call for 3 sticks (24 tbs.) of butter in the frosting. The correct amount is 2 sticks (16 tbs.) of butter.**
White layer cakes have been the classic birthday cake for more than 100 years. White cake is simply a basic butter cake made with egg whites instead of whole eggs. The whites produce the characteristic color, and they are also supposed to make the cake soft and fine-grained—that’s what we wanted. Unfortunately, the white cakes that we have baked over the years, though good enough, always fell short of our high expectations. They came out a little dry and chewy—one might say cottony—and we noticed that they were riddled with tunnels and small holes. What were we doing wrong?
Every traditional recipe for white cake calls for stiffly beaten egg whites folded into the batter at the end. We began to suspect that it was the beaten egg whites that were forming the large air pockets and those unsightly holes in the baked cakes. We solved this problem by mixing the egg whites with the milk before beating them into the flour-and-butter mixture. The results were fantastic. The cake was not only fine-grained and free from holes but, to our surprise, it was also larger and lighter than the ones we’d prepared with beaten whites. And the method couldn’t be simpler, quicker, or more foolproof. To make this cake birthday-special, we iced it with an easy butter frosting and added a layer of raspberry jam and chopped toasted almonds.
If you have forgotten to bring the milk and egg white mixture to room temperature, set the bottom of the glass measure containing it in a sink of hot water and stir until the mixture feels cool rather than cold, around 65 degrees. Cake layers can be wrapped and stored for one day; frosting can be covered with plastic wrap and set aside at room temperature for several hours. Once assembled, the cake should be covered with an inverted bowl or cake cover and refrigerated. Under its coat of frosting, it will remain fresh for up to three days. Bring it to room temperature before serving. There is enough frosting to pipe a border around the base and top of the cake. If you want to decorate the cake more elaborately, you should make one and a half times the frosting recipe. You may also substitute lemon curd for the raspberry jam in the filling. If desired, finish the sides of the cake with 1 cup of sliced almonds.