Classic Cream Cheese Frosting

4 ounces original cream cheese, softened (not low-fat or fat-free varieties) 1/4 cup unsalted butter, softened2 cups powdered sugar, not sifted1 teaspoon vanilla extract3 tablespoons sour cream (not fat-free variety)In a large mixing bowl, beat cream cheese and butter until light and creamy. Add powdered sugar, vanilla and sour cream. Beat on low speed until combined. Scrape bowl well.Beat on high speed until smooth and creamy, about 3 minutes. If frosting feels too thick, add 1-2 teaspoons more sour cream. Store refrigerated, tightly covered.Makes 2 cups; enough for the top of a 9-by-13-inch cake or 20-24 cupcakes.Baker's hint: To frost top and sides of a two-layer cake, double the recipe.Nutrition values per serving: 92 calories, 5 g fat (3 saturated fat), 12 g carbohydrates, trace g fiber, 1 g protein, 13 mg cholesterol, 18 mg sodium.