Make the Cupcakes: Adjust oven rack to middle position and preheat oven to 350°F. Line 20 muffin cavities with paper liners or grease with gluten-free non-stick cooking spray.
Make the Frosting: In a bowl, combine cream cheese and butter. Cream until smooth. Add confectioners' sugar, milk and vanilla. Cream until smooth. Icing should be spreadable. If needed, add an additional 1/2 tablespoon milk. Spread icing on cooled cupcakes. Cupcakes can be stored for up to three days at room temperature or frozen for one month.