Yellow Genoise Cake

Preheat oven to 350 degrees. Butter a 12-by-18-inch standard jelly-roll pan, line with parchment paper, butter and flour the paper, and set aside.

Set the metal bowl of an electric mixer over, but not in, a pot of simmering water. Combine sugar and eggs in the bowl, and whisk until mixture is warm to the touch, about 2 minutes.

Transfer the bowl to an electric mixer fitted with the whisk attachment, and beat on high speed until mixture is very thick and pale, 6 to 8 minutes. With a rubber spatula, gently transfer mixture to a large clean mixing bowl. Sift in flour in three additions, folding gently after each. In a small bowl, combine butter and vanilla, then add in a steady stream as you fold in the third addition of flour. Fold gently, and pour out onto prepared pan. Smooth top with offset spatula.

Bake until cake is springy to the touch and golden brown, 18 to 20 minutes. Remove from oven, and let cool on a wire rack. Wrap tightly with plastic wrap, and refrigerate for up to 3 days or freeze for up to 1 month. When ready to use, turn out cake onto a cutting board covered with a clean piece of parchment or wax paper, and peel the paper off the cake.