I use this frosting sometimes on the Chocolate Raspberry Mousse Cake instead of ALL chocolate!
Puree the raspberries and then run the pureed berries through a sieve. You should have about 1/2 cup puree.
Add the softened butter and the raspberry puree to a stand mixer and mix till they are completely combined.
Add half the powdered sugar.
Continue to beat on medium speed until the frosting is creamy.
Continue adding the powdered sugar 1/2 cup at a time until you have the consistency desired.
1 cup butter, softened
5 cups powdered sugar
1 6-8 oz. clamshell fresh raspberries