In the bowl of an electric mixer fitted with a paddle attachment, or large bowl with a hand held mixer beat the butter and peanunt butter together for 5 full minutes until light and fluffy.
Mix the butter and peanut butter
Sieve the powdered sugar to prevent any lumps and add half to butter. Beat for 2 minutes then add the remaining powdered sugar, cream, vanilla, and salt and mix for 3 more minutes.
Add the powdered sugar
Spread or pipe frosting. Store in the fridge for up to 7 days, let come to room temperature and mix before using.
Pipe the frosting