Flourless chocolate cake

Method

1. Start. Melt chocolate and butter. Whisk yolks with half the sugar; combine.Watch for: Use gentle heat and stir often; remove from the heat as soon as the mixture is uniform so residual heat does not take it too far. Scrape the bottom and sides once, then stop at the texture described; extra mixing can add air or develop unwanted gluten.
2. Then. Whip whites with remaining sugar to medium peaks; fold in thirds.Watch for: Use a clean bowl and check the stated stage by lifting the whisk; stop as soon as the foam holds that shape. Cut through the center and sweep up the side while rotating the bowl; stop when the last dry streak disappears so you preserve air and tenderness.
3. Finish. Bake in an 8-inch pan 30–36 minutes; cool fully.Watch for: Keep it covered during the rest; move on only when it is evenly cool or firm, including at the center. Begin checking at the early end of the range; use the stated color, movement, or internal-temperature cue rather than time alone.