Place the butter and peanut butter into a medium bowl, and beat with an electric mixer. Gradually mix in the sugar, and when it starts to get thick, incorporate milk one tablespoon at a time until all of the sugar is mixed in and the frosting is thick and spreadable. Beat for at least 3 minutes for it to get good and fluffy.
Once cupcakes are cool, frost tops with peanut butter frosting. Place a dollop of Bonne Maman Strawberry Preserves in center of frosting. Decorated cupcakes will keep, covered and refrigerated, for up to 2 days.