Spray 4 6-ounce ramekins with nonstick cooking spray and dust with cocoa powder. This ensures the cakes will seamlessly come out of the ramekins when inverted onto a plate in step 6.

Preheat oven to 425°F (218°C).

Coarsely chop the chocolate. Place butter into a medium heat-proof bowl, then add chopped chocolate on top. Microwave on high in 10 second increments, stirring after each until completely smooth. Set aside.

Whisk the flour, confectioners’ sugar, and salt together in a small bowl. Whisk the eggs and egg yolks together until combined in another small bowl. Pour the flour mixture and eggs into the bowl of chocolate. Slowly stir everything together using a silicone spatula or wooden spoon. If there are any lumps, gently use your whisk to rid them. The batter will be slightly thick.

Spoon chocolate batter evenly into each prepared ramekin. Top with peanut butter and use a spoon to slightly press it down into the batter. Some may still be exposed—see photo above for a visual.

Place ramekins onto a baking sheet and bake for 12-13 minutes until the sides appear solid and firm. The top may still look slightly soft. Allow to cool for 1 minute, then cover each with an inverted plate and turn over. Use an oven mitt because those ramekins are hot! The cakes should release easily from the ramekin. Top with ice cream and melted peanut butter and/or chocolate syrup for serving, if desired. Serve immediately.