Prepare Chocolate Mixture:

In a double boiler, melt the dark chocolate and butter together until smooth. Remove from heat and let cool slightly.
Mix Eggs and Sugar:

In a separate bowl, whisk together eggs, egg yolks, and granulated sugar until the mixture becomes pale and fluffy.
Combine and Bake:

Gently fold the melted chocolate mixture into the egg mixture. Add flour, vanilla extract, and a pinch of salt; fold until just combined.
Grease ramekins with butter and pour the batter into each, filling up to ¾. Push a marshmallow into the center of each ramekin.
Bake in a preheated oven at 200°C (392°F) for 10-12 minutes, or until the edges are firm but the center is still soft.
Serve with Toppings:

Remove from oven and let sit for 1-2 minutes. Invert each cake onto a plate. Top with a dollop of whipped cream, drizzle with melted chocolate, and sprinkle crushed graham crackers for that final touch.
Prep Time: 15 minutes | Cook Time: 12 minutes | Servings: 4