1. Preheat the oven to 200°C (390°F). Grease a mini muffin tin* and set aside. Melt the butter and let cool down a bit.

2. Add the melted butter, sugar and vanilla extract to a large bowl and mix on high speed until well combined. Add the egg and mix in. Mix the flour with cocoa, baking powder, and salt. Add to the bowl and mix until just combined. Fold in the chopped chocolate.

3. Fill the molds of the mini muffin tin about 3/4 full (works best if you use a piping bag) and bake for about 8-10 minutes or until a toothpick inserted into the center comes out clean. Take out of the oven and press the Toffifay into the still warm mini muffins, then let cool down a bit. Remove from the tin and let cool down completely on a wire rack.