This French buttercream frosting is great for our Genoise cake recipe and your run-of-the-mill cupcakes as well! Add cocoa powder, matcha, lemon extract, or other flavoring if you please; this buttercream is the great base for other, interesting flavors.
Yield: moderate layer for single sheet pan cake. Add 50% water for thick frosting
18 oz (4.5 sticks) very soft butter
16 egg yolks
½ cup water
2 ½ cups sugar
1 TBSP coffee extract
Work the butter into a soft cream by beating it with a wooden spoon. Set aside.
Place the egg yolks in a large mixing bowl and beat for about 2 minutes.
Put the water in a small saucepan and add the sugar. Without stirring, bring to a boil on medium heat. Boil for a few minutes until the syrup reaches 240°F. Remove immediately from heat.
Beating the egg yolks continually, slowly add the hot syrup, aiming it in a thin stream between the side of the mixing bowl and the beating whisk. When all of the syrup has been incorporated continue beating until the mixture has cooled to room temperature. This will take several minutes at least.
Next add the butter 1 tablespoon at a time, beating well after each addition. Once all of the butter has been incorporated, add the coffee extract. Continue beating until the buttercream attains frosting consistency. Don't despair if it seems runny, just keep beating.