• 1/3 cup butter; softened
• 3-4 cups icing sugar
• ¼ cup milk
• 1 tsp. vanilla
• ¼ cup raspberries

1. Mix all together to spreading consistency. Add more milk or sugar to get the consistency you want.
2. Pipe onto cupcakes.

I just basically took your run-of-the-mill buttercream frosting recipe and threw in raspberries but if you must have a recipe...