Chocolate Fudge Frosting

1 stick butter
1/2 c heavy whipping cream
1/2 c sugar
3 oz espresso chocolate chunks
4 oz unsweetened chocolate
2 1/2 c powdered sugar
pinch of cinnamon
1 tsp vanilla

Melt butter, sugar, and cream in saucepan over medium heat until sugar is dissolved.  Pour over chocolate pieces and stir briskly until chocolate is melted.  Add powdered sugar and vanilla and whisk until smooth.  Refrigerate until cool and then whip to desired consistency.