This creamy & fluffy cookie sandwich frosting tastes like ice cream and is perfect for pairing with any cookie (like my mini m&m cookies!) or cookie cake! Makes roughly 1 ½ cups frosting, enough to fill 12 cookie sandwiches.
Beat the softened ½ cup unsalted butter (i.e. 1 stick[/adjustable]) on medium-high speed for 2 minutes until smooth. Turn the mixer to low speed then add the 2 ½ cups powdered sugar. You may need to stop and scrape down the sides.
Add 2 teaspoons vanilla extract and ⅛ teaspoons salt and turn mixer to medium speed. One tablespoon at a time, add 2-3 tablespoons milk or heavy cream. Beat on high for 2-3 minutes until creamy and the frosting is at a good consistency to pipe. If it looks too runny, add more powdered sugar. If it looks too stiff, add a tiny bit of milk until you get to the desired consistency.
This will make just enough frosting to fill about 12 cookie sandwiches (2 tablespoons of frosting each) or to pipe a border & add a message to a round cookie cake.