Step 1 Heat the oven to 350 degrees. Butter and flour a 9-inch round cake pan.
Step 2 Combine the egg yolks and 3/4 cup sugar in a mixing bowl, whisking until thick and light. Stir in the vanilla.
Step 3Beat the egg whites and salt until they form soft peaks. Add the remaining 2 tablespoons of sugar and beat until glossy, 15 to 20 seconds.
Step 4Incorporate 1/3 of the whites into the yolk mixture. Sift 1/4 cup of the flour over the mixture and fold it in. Repeat, folding in whites and flour, until the last flour is nearly incorporated. Fold in the butter.
Step 5Pour the batter into the pan. Bake just until the cake pulls away from the pan, 30 minutes. Cool slightly before unmolding.