Make the frosting: place butter in the bowl of a stand mixer and beat for 5 full minutes at medium speed. (lapechefraiche.com)
While the crust is baking, place the cream cheese and the peanut butter in the bowl of a standing mixer and beat on medium speed with the paddle attachment until smooth. (the-broken-bread.com)
Beat sugar and butter in bowl with electric mixer until light and fluffy. (vegetariantimes.com)