Directions:
In the bowl of a stand mixer fitted with a whisk attachment, combine powdered sugar, butter, peanut butter and salt. Mix on low speed until just combined, then switch to high speed.
Add heavy cream one tablespoon and beat until mixture is lightened and smooth. Transfer to a piping bag or zip-top bag with the corner snipped. Pipe onto cooled cupcakes.
Garnish with jimmies, ground peanuts and a sprinkling of sea salt.