Put the chocolate in a heat-proof bowl, and melt over a pan of hot water. Set aside and add the butter stirring until smooth and homogenous. Add the heavy whipping cream, the walnuts, vanilla and the desired flavoring and mix until fully incorporated.

Allow to cool, then put in the refrigerator for two hours until it is hard enough to roll, Remove and using a teaspoon roll out balls. Roll in your hands quickly and put them on a parchment paper-covered baking sheet and refrigerate for 1 hour.