Enriched with a little butter, this is a rich, moist cake of Italian origin, and has no equal for versatility—excellent with fruit fillings, as a roll cake with cream fillings, or as a foil for a simple glaze or fresh fruit. This recipe makes two 1-inch layers or one 2-inch layer that can be split into 3 or 4 thin layers. Clarified butter gives a superior result, but regular butter will do. You’ll need to begin with a bit more butter to get the 5 ⅓ tablespoons needed if you choose to clarify it. To make a thin sheet for roll cakes and charlottes, bake as for Cake Sheet for Roll Cakes.

Have all ingredients at room temperature, about 70°F. Preheat the oven to 350°F. Grease and flour the bottom(s) of two 9 × 2-inch round cake pans or one 9-inch springform pan and line the bottom(s) with rounds of parchment paper.

Sift together 3 times and return to the sifter:

Melt in a small saucepan:

Set aside. Whisk together in a large heatproof bowl or a stand mixer bowl:

Set the bowl in a skillet of barely simmering water and whisk constantly until the mixture is warm to the touch (about 110°F). Remove the bowl from the heat and beat on high speed with a hand mixer, or in a stand mixer with the whisk attachment, until the mixture is lemon colored, has tripled in volume, and has reached the stage known as au ruban—like a continuous flat ribbon when dropped from a spoon (about 5 minutes in a stand mixer, 10 to 15 minutes with a handheld mixer). In 3 additions, sift the flour mixture over the top and fold in very gently with a silicone spatula. Reheat the butter until it is hot and transfer to a medium bowl. Fold about 1 ½ cups of the egg mixture into the butter until completely incorporated, along with:

Scrape the mixture onto the remaining egg mixture and fold in. Scrape the batter into the pan(s) and spread evenly. Bake until the cake begins to pull away from the sides of the pan(s) and the top springs back when lightly pressed, about 15 minutes in cake pans, 30 minutes in a springform pan.

Let cool in the pan(s) on a rack for 10 minutes. Slide a thin knife around the cake to detach it from the pan(s); remove the ring of the springform pan, if using. Invert the cake and remove the paper liner(s). Let cool right side up on the rack.