After making batch after batch of the regular Wilton buttercream, I was ready to try something different. This buttercream reminds me of the peanut butter ice cream we've made over and over. It was really light (not in calories!) and fluffy. It went great with the chocolate cake I made for the final cake for Course 3. This recipe comes from Wilton's Cupcake Fun site.
1/3 cup solid vegetable shortening
1/3 cup butter
3/4 cup peanut butter
3/4 cup milk
1 teaspoon Pure Vanilla Extract
4 cups sifted confectioners' sugar (approx. 1 lb.)
Yield: Make about 3 cups icing.
Cream shortening and butter with electric mixer.
Add peanut butter, milk and vanilla.
Gradually add sugar, one cup at a time, beating well on medium speed. Scrape sides and bottom of bowl often. When all sugar has been mixed in, icing will appear dry.
Add milk and beat at medium speed until light and fluffy. (I was confused at this last instruction as it says to add the milk above. So, I added 1/2 with the peanut butter and vanilla, and half at this step.)
Keep icing covered with a damp cloth until ready to use. For best results, keep icing bowl in refrigerator when not in use. Refrigerated in an airtight container, this icing can be stored 2 weeks. Re-whip before using.