Charlotte Biscuit Base
Preheat oven to 375 degrees. Draw a 5-inch, 9-inch, and 11-inch circle on parchment. Line a baking sheet with parchment paper. In the bowl of a mixer fitted with the whisk attachment, whisk egg yolks on high speed with 1/2 cup sugar until thick and pale, about 7 minutes; set aside. In a clean bowl, whisk egg whites on medium speed until foamy; slowly add remaining sugar and cream of tartar. Whisk on high speed until stiff peaks form, 10 minutes.Advertisement
Transfer egg whites to a large bowl. Gently fold in the yolk mixture, and then fold in cake flour in 2 additions. Using an offset spatula, spread the batter inside each circle.
Bake 10 minutes or until lightly golden. Allow to cool completely on a wire rack.