Beat the butter until fluffy. In a large mixing bowl, beat the softened butter with an electric mixer on medium speed for 2-3 minutes until it’s pale and very fluffy. This initial beating incorporates air for a lighter texture.
Add the peanut butter and continue beating for another 2 minutes until the mixture is completely smooth and well-combined. Scrape down the sides of the bowl with a rubber spatula to ensure even mixing.
Gradually add the powdered sugar, one cup at a time, mixing on low speed after each addition until incorporated. This prevents the sugar from flying everywhere and helps achieve a smooth texture.
Pour in the cream, vanilla, and salt, then increase the mixer to medium-high speed and beat for 3 minutes until the frosting becomes light and fluffy. The extended beating time is crucial for the perfect texture.
Assess the consistency of your frosting. It should be smooth and hold its shape when the beater is lifted. If it’s too thick, add additional cream, one tablespoon at a time. If too thin, add more powdered sugar, 1/4 cup at a time.
Use immediately or store properly. The frosting can be used right away or covered tightly and refrigerated for up to 5 days. If refrigerated, bring to room temperature and re-beat briefly before using.