Prep Your Mixer: Grab your handheld or stand mixer and attach the paddle or whisk.
Cream the Butter: Beat the softened butter on medium speed until it's light and creamy, which usually takes about 2 minutes.
Combine Ingredients: With the mixer on low speed, slowly add in the peanut butter, confectioners' sugar, heavy cream, vanilla extract, and salt.
Whip to Perfection: Once everything is in, increase the mixer speed to high and beat for a full 3 minutes. This will make your frosting incredibly light and fluffy!
Adjust as Needed: If you find your frosting a bit too thin, you can add up to 1/4 cup more confectioners' sugar, a little at a time. If it's too thick, simply add another Tablespoon of heavy cream.
Store It: Cover your finished frosting tightly and keep it in the refrigerator for up to 1 week. Enjoy!