Watts' Tea Shop, a Milwaukee staple with deep historical roots, has served this bright, fluffy layer cake for their afternoon tea service since the early 1900s.
For the Cake
- 18 large eggs, separated
- 2 cups sugar
- 2 tsp. cream of tartar
- 1⁄2 tsp. salt
- 2 tsp. pure vanilla extract
For the Filing and Frosting
- 8 large egg yolks, plus 1 1/2 cups egg whites
- 1 1⁄2 cups powdered sugar
- 1 1⁄2 cups milk
- 2 cups softened unsalted butter
- 3 tsp. pure vanilla extract
- 3 cups granular sugar
- 1 1⁄2 cups water
- 3 tsp. cream of tartar
- 1 pinch salt
Make the cake: Heat oven to 350˚. In a mixer with a whisk attachment, beat on high egg whites, 1 cup sugar, cream of tartar, and salt until a medium peak. In a second bowl, beat egg yolks, vanilla, 1⁄2 cup water, and remaining sugar until the mixture turns pale yellow and doubles in volume. Turn mixer on low and slowly add the flour in three parts. Gently fold egg yolk mixture into the egg white mixture in three parts until blended smoothly. Divide mixture between two 10'' ungreased angel food-cake pans and bake for 45 minutes. Let each cake cool upside down, then cut into 3 layers (see How to Cut Cake Layers).
Make the filling: In a double boiler, slowly cook egg yolks, powdered sugar, and milk until mixture thickens, then pour into a flash dish to cool thoroughly. Once custard is cooled, cream butter and 1 tsp. vanilla extract with an electric mixer set to high, stopping occasionally to scrape the bowl with a rubber spatula; add custard with the mixer on low until fully blended.
Make the frosting: In a medium saucepan, boil granular sugar and water until the temperature reaches 300˚ and the mixture is a light amber color and has the consistency of corn syrup. With a mixer, beat egg whites, salt and cream of tartar to a soft peaks. Slowly add sugar syrup in a steady stream and 2 tsp. vanilla; whip until cooled.
Assemble the cake by spreading filling between layers and covering with frosting.