Yellow Sponge Cake

Preheat oven to 350 degrees. Butter a rimmed baking sheet and line with parchment; set aside. On a piece of parchment, sift together flour and cornstarch; set aside.

In the bowl of an electric mixer fitted with the whisk attachment, combine eggs, sugar, salt, and vanilla. Beat on high speed until mixture is thick and holds a ribbon-like trail on surface when whisk is raised, about 5 minutes.

Holding parchment like a funnel, gradually add flour mixture to egg mixture in two batches. With machine running on low speed, mix until just combined. In a steady stream, add butter; mix until just combined. Remove bowl from mixer; detach whisk. Using the whisk, fold mixture several times.

Spread batter evenly into prepared sheet. Bake until center springs back when lightly touched and edges pull away from sides, 20 to 24 minutes. Transfer to a wire rack and let cool completely.