Combine the chocolate chips and margarine in a microwave-safe bowl. Heat in the microwave at 30 second intervals, stirring between each until melted and smooth. Mix in the coffee beans until evenly distributed.
Pour the chocolate out onto the baking paper and spread into an even layer. Sprinkle the pieces of white chocolate evenly over the top and press in lightly to make sure they stick. Place in the freezer until set, about 5 minutes. Break into pieces and store in an airtight container.