Chop the chocolate and place it in a microwave-safe bowl with the butter cut into small pieces. Microwave for 40 seconds at 600W, let it rest for 15 seconds, then microwave again for 20 seconds at 600W. Mix with a spatula, preferably silicone.

Add the orange zest and rum, and continue mixing until you have a smooth cream.

Refrigerate the cream for about 4 hours until it has enough consistency to form the truffles.

Shape the mixture into small balls using a teaspoon and roll them in a plate of pure cocoa powder.

Once formed, place them back in the refrigerator to regain the right consistency. Take them out of the fridge 5 minutes before serving.