This homemade peanut butter frosting recipe is amazing–it balances flavor against sweetness well, and the texture is perfect: creamy, fluffy, not oily at all.
Just a word of warning: Do not use margarine; use butter. Butter will give you beautiful, fluffy icing (and that’s what you want).

Peanut Butter Frosting Recipe
FLUFFY PEANUT BUTTER FROSTING
1-1/4 cups homemade peanut butter, room temperature
1/2 cup butter, room temperature
1-1/2 cups powdered sugar
2 to 3 TBS heavy cream, room temperature
1/2 tsp pure vanilla extract
Beat the peanut butter and butter for several minutes until really creamy.
Gradually add the powdered sugar and beat well after each addition. Â Add the cream and vanilla extract; beat for 3 to 4 minutes.