- 4 eggs
- 1⁄2 cup sugar
- 3⁄4 cup cake flour, sifted
- 3 Tbs. unsalted butter, melted
In the bowl of a stand mixer, whisk together the eggs and sugar by hand until combined. Place the bowl over but not touching simmering water in a saucepan and gently whisk until the mixture registers 140°F on an instant-read thermometer, about 3 minutes. Put the bowl on the mixer fitted with the whisk attachment and beat on high speed until the mixture is pale and almost tripled in volume, 5 to 8 minutes.
Remove the bowl from the mixer. Sift the flour over the egg mixture in two additions and carefully fold in with a large rubber spatula. Fold a large dollop into the melted butter, then fold back into the egg mixture.
Pour the batter into the prepared pan and smooth the top. Bake until the top is browned, about 20 minutes. Transfer the pan to a wire rack and let cool completely. Run a table knife around the edge of the pan and invert the cake onto a work surface. Turn the cake right side up. Use as directed in the specific recipe for a layer cake or jelly roll.