Yep! You read that right – I sat on my deck last week trying to decide on a sewing project, but I just kept wondering if I could take my regular swiss meringue buttercream recipe and make it peanut butter. I skipped the sewing and spent the rest of the day in cake heaven. Peanut butter buttercream, as it turns out, is extra delicious!! This recipe comes out a little soft for piping, and I originally used it in a chocolate peanut butter layer cake (which I’ll share soon), but I did put the extra in the fridge for a few days and when I rewhipped it, it actually did pipe just fine and hold its shape. I wouldn’t try to use this recipe to pipe any intricate designs, but if you need a peanut butter fix – this is it!
Basically, you’ll make a regular swiss meringue buttercream and then soften/melt peanut butter chips in a double boiler before stirring them into the buttercream. So good! Sweet and creamy, but fluffy and light at the same time.
When it comes time to pipe the peanut butter frosting onto cupcakes or a cake – you can use a nice big tip like #1M (my favorite) or #2D. The two tips pipe out pretty similar – they’re both star tips – but the 2D makes the swirl curve over on itself just a bit vs. the sharper swirl of 1M. The 2D would work especially well if you just wanted a simple flat swirl – like on my Swirled Roses Cake. Either the 1M or the 2D will work fine.. Fill your piping bag (fitted with tip) with frosting. Beginning just inside the outer edge of the cupcake, begin swirling in a counter-clockwise direction, slightly overlapping to the inside as you go around and up each time. When you reach the top, lift the piping bag straight up from the center to make a point as you release pressure from the bag. Done!
You can add sprinkles for extra fun! The gold is great for a more sophisticated look!
Okay! Ready for the recipe?
- 5 egg whites
- 1 C. granulated sugar
- 1 1/2 C. butter softened slightly
- 1 tsp. vanilla extract
- 1 C. peanut butter chips
- Combine egg whites and granulated sugar in the heatproof bowl of a standing mixer.
- Set the mixer bowl over a small pan of simmering water and whisk egg mixture until warm to the touch and completely smooth (check with your fingers to be sure all the sugar has dissolved).
- Remove mixer bowl from pan and attach to your standing mixer.
- Turn your mixer on low and gradually up to high speed with the whisk attachment.
- Continue mixing for about 8-10 minutes, or until the bottom of the mixing bowl is cool to the touch.
- The egg mixture should be glossy white and fluffy and COOL!
- Add in butter, 1-2 tablespoons at a time, until completely mixed in.
- Whisk in vanilla extract.
- In a double boiler (or heatproof bowl over simmering pan of water), heat 1 cup of peanut butter chips until soft and you can stir them into a paste.
- Remove from heat and let cool slightly.
- Whisk peanut butter paste into buttercream until completely mixed.
- Switch to the paddle attachment and continue mixing buttercream for 2-3 minutes more.
- If frosting is too soft to pipe, place in refrigerator for a little while to help firm it up.