1. Prepare the Chocolate Base

Preheat your oven to 180°C (350°F). Melt the dark chocolate and butter together in a double boiler or microwave (in 30-second intervals). Stir until completely smooth and combined.

2. Mix the Ingredients

In a mixing bowl, whisk the eggs and granulated sugar together until the mixture turns pale and slightly thickened. Add the melted chocolate mixture to the eggs and sugar, and mix until well combined.

3. Add Dry Ingredients

Gradually fold in the flour, baking powder, and a pinch of salt. Stir the mixture gently until you achieve a smooth, lump-free batter.

4. Assemble the Muffins

Spoon about one tablespoon of batter into each muffin mold (greased or lined with paper cases). Place a square of chocolate in the center of each mold. Cover with another spoonful of batter to fully conceal the chocolate square.

5. Bake the Muffins

Bake in the preheated oven for 10–12 minutes. Be careful not to overbake—you’re aiming for a soft, molten center. Keep an eye on them during the last few minutes to ensure they don’t cook through entirely.

6. Cool and Serve

Remove the muffins from the oven and let them cool in the mold for 5 minutes before removing them. Serve warm to enjoy the molten chocolate center. If you prefer a firmer texture, allow them to cool completely.