Three ingredients are all that stand between you and the ultimate milk chocolate frosting.
In large microwave-safe bowl, combine chocolate and cream. Heat in microwave at 50 percent power for 1 minute. Stop microwave and stir with rubber spatula. Heat in microwave at 50 percent power until melted, 1 to 2 minutes. Remove bowl from microwave.
Add softened butter to chocolate mixture and use whisk to stir and break up large butter pieces. Let sit until butter is fully melted, about 5 minutes. Whisk until completely smooth.