Preheat your oven to 425°F (218°C). Generously grease four 6-ounce ceramic ramekins with melted butter using a pastry brush. Dust the interiors completely with unsweetened cocoa powder, tapping out any excess. This ensures the lava cakes release effortlessly onto plates without tearing.

Place the finely chopped bittersweet chocolate and cubed butter into a heatproof glass bowl. Microwave in 30-second increments at 50% power, stirring between each burst, until completely melted, glossy, and smooth. Set aside to cool slightly for 3 minutes.

In a medium mixing bowl, whisk together the whole eggs, egg yolks, sifted powdered sugar, vanilla extract, and sea salt with a wire whisk or hand mixer for 2 minutes until pale, slightly thickened, and frothy.

Pour the melted chocolate-butter mixture into the whipped egg mixture. Gently fold together with a silicone spatula until thoroughly combined and velvety.

Sprinkle the flour over the batter and fold very gently just until no flour streaks remain. Be careful not to overmix to keep the cake crumb tender and delicate.

Divide the batter evenly among the four prepared ramekins (about 3/4 full each). Place the ramekins onto a rimmed baking sheet.

Bake at 425°F (218°C) for precisely 12 to 14 minutes. The cake edges should look firm, puffed, and fully baked, while the center dome remains slightly soft and jiggly.

Remove from the oven and allow to rest for exactly 1 minute. Run a thin paring knife around the edges of each ramekin to loosen. Place a small dessert plate over each ramekin and carefully invert using an oven mitt. Let sit inverted for 10 seconds, then gently lift the ramekin away to reveal the warm cake.

Dust immediately with powdered sugar, top with a scoop of cold vanilla bean ice cream and fresh raspberries, and pierce the center with a spoon to release the warm molten fudge!