In a small saucepan, heat heavy cream over medium heat just until boiling point. Pour it over the chocolate. Let it melt undisturbed for two minutes, and then slowly mix with a spatula until smooth. Stir in Kahlua.
Pour the mixture into a shallow dish (I used 8x8in(20x20cm) baking pan) and chill for at least 2 hours in the fridge, until set.
Crush the M&M’s with a rolling pin until desired fineness. I like it pretty fine with some colorful specks.
Using a medium cookie scoop, form the chocolate mixture into 1.5-inch (about 3.5cm) balls and roll in the crushed M&M’s. Keep refrigerated for up to 5 days.