To make a traditional cream cheese frosting for carrot cake, beat 8 ounces of cream cheese, 1/4 cup butter or margarine and 1 teaspoon vanilla extract until blended, then gradually add 16 ounces of powdered sugar. Multiply the recipe for a large cake if needed.
The Food Network website has a recipe that adds a twist to the traditional cream cheese frosting with lemon. The recipe calls for four packages of cream cheese, 1/2 cup butter or margarine, 1 2/3 cups powdered sugar, 1 teaspoon vanilla extract and 1 tablespoon of lemon juice. Substitute orange juice for the lemon juice for an orange-flavored alternative. This recipe makes enough frosting for a 9-inch by 13-inch cake.
Vanilla frosting also goes well with carrot cake. RachaelRaymag.com has a recipe for fluffy vanilla frosting made specifically for carrot cake. It includes a recipe for carrot cake, but you can just make the frosting at the end of the recipe if you already have a preferred cake recipe. The fluffy vanilla frosting calls for four egg whites, 1/2 teaspoon cream of tartar, 1 1/2 cups sugar, 1/4 teaspoon salt, 1/2 cup cold water and 2 teaspoons of vanilla extract. The eggs and cream of tartar in this recipe make it thick and fluffy.