Step 1

Heat oven to 350ºF.

Step 2

Beat 2 oz. cream cheese and sour cream in large bowl with mixer until blended. Add egg whites and cake mix; mix well. Pour into 2 (9-inch) round pans sprayed with cooking spray.

Step 3

Bake 30 min. or until toothpick inserted in center comes out clean. Cool 10 min.; remove from pans. Cool completely.

Step 4

Meanwhile, beat remaining cream cheese, butter, vanilla and sugar with mixer until well blended. Refrigerate until ready to use.

Step 5

Fill and frost cake layers with frosting before serving.