This raspberry frosting recipes can be used on vanilla or chocolate cupcakes.
In a blender or food processor, puree fresh raspberries and milk. Put pureed raspberries into a mesh sieve, push out as much liquid as you can. Set aside.
Cut up butter and shortening and put them in a mixing bowl. Mix them on high speed until light and fluffy.
Add in confectioners' sugar and raspberry liquid, mix slowly until incorporated, them mix on high speed for at least 10 minutes or longer. (you can't over mix this, the longer the better)