Prep: Spray four 6-ounce ramekins (or half of a 12-cup muffin pan) with nonstick spray and dust with cocoa powder. This helps the cakes release easily later.

Preheat Oven: Preheat to 425°F (218°C).

Melt Chocolate and Butter: Chop the chocolate. In a medium heatproof bowl, microwave the butter and chocolate together in 10-second bursts, stirring between each, until smooth. Set aside.

Mix Dry Ingredients: In a small bowl, whisk together the flour, confectioners’ sugar, and salt.

Combine: In another bowl, whisk eggs and yolks. Add the flour mixture and eggs to the chocolate mixture. Stir gently with a silicone spatula or wooden spoon until smooth and slightly thick.

Bake: Divide batter evenly among ramekins or muffin cups. Place ramekins on a baking sheet and bake for 12–14 minutes (8–10 minutes for muffin pan), until the edges are set but the centers look soft.

Invert and Serve: Cool for 1 minute, then carefully invert onto plates. If using a muffin pan, gently lift the cakes out with a spoon. Top as desired and serve immediately.