[header] How to make easy sour cream chocolate frosting [title] Melt 2 cups (450 g) semisweet, milk or dark chocolate chips slowly in double boiler or in heat safe container in the microwave, stirring every 20 seconds. [step] Remove immediately from the burner or microwave once chocolate has melted and stirs smoothly. Do not over heat or you will scorch the chocolate and will not be able to use it. 
[title] Make sure butter is at room temperature so it will disperse properly, add 8 tbsp. [step] ( 120 g) of butter to the melted chocolate and stir.