The Ribbon Stage

When a cake has little or no chemical leavening — sponges, génoise, lava cakes, mousse-based batters — the eggs do all the lifting, and the lift is built before the flour goes in. Whisk whole eggs (and sometimes extra yolks) with sugar on high speed until the mixture roughly triples in volume and turns thick, pale, and mousse-like. The test is the ribbon: lift the whisk, and the batter should fall back on itself in a thick stream that sits on the surface as a visible ribbon for two or three seconds before sinking. A stand mixer on high takes 4–6 minutes; a hand whisk noticeably longer. Under-whisked eggs are the single most common reason these cakes come out dense and flat — the air folded in here is what bakes into the crumb. Once the ribbon is established, fold subsequent ingredients in gently: aggressive mixing knocks the air straight back out and undoes the work.