Peppermint and Cream Cheese Filling

In a large bowl, combine two 3-ounce packages cream cheese, softened; 3 tablespoons butter, softened; and 1/2 teaspoon peppermint extract. Beat with an electric mixer on medium speed until light and fluffy. Gradually beat in 3 cups powdered sugar. If necessary, add milk (1 teaspoon at a time) to make a filling of spreading consistency.