Lightly coat four 6-ounce ramekins with nonstick cooking spray and dust the insides with cocoa powder to help the cakes release easily when inverted in step 7. Alternatively, you can spray and dust half of a 12-cup muffin pan; if using this method, the recipe will make 6 cakes.

Preheat your oven to 425°F (218°C).

Roughly chop the chocolate and place it in a medium heatproof bowl along with the butter. Microwave in 10-second intervals on high, stirring after each, until the mixture is smooth and fully melted. Set it aside.

In a separate small bowl, whisk together the flour, confectioners’ sugar, and salt. In another small bowl, whisk the eggs and egg yolks until well combined. Add both the flour mixture and the egg mixture to the bowl of melted chocolate. Stir slowly and gently with a silicone spatula or wooden spoon until fully incorporated. If you notice any lumps, use a whisk to smooth out the batter. The finished batter should be somewhat thick.

Evenly divide the chocolate batter among the prepared ramekins or muffin cups.

Place the filled ramekins on a baking sheet and bake for 12–14 minutes, or until the edges are set and firm while the tops remain soft. *If using a muffin pan, bake for only 8–10 minutes.

Let the cakes cool for 1 minute. Then, using an oven mitt (as the ramekins will be hot), cover each ramekin with an inverted plate and carefully flip to release the cakes. *If you used a muffin pan, gently scoop out the cakes with a spoon and place them upside down on serving plates.

Top with your choice of ice cream, fresh berries, and/or chocolate syrup. Serve right away.