1 package (2-layer size) white cake mix
1 pkg. (4 serving size) Jell-O Lemon Instant Pudding
1 cup water
4 egg whites
2 tablespoons oil
3 3/4 cups icing sugar
1 (250 g) package Philadelphia Light Brick Cream Cheese, softened
1/4 cup butter, softened
2 tablespoons lemon juice

Preheat oven to 350 degrees F (175 degrees C). Beat cake mix, dry pudding mix, water, egg whites and oil in large bowl with electric mixer on low speed until moistened. (Batter will be thick.) Beat on medium speed 2 minutes. Spoon batter evenly into 24 paper-lined muffin cups.
Bake 21 to 24 minutes or until wooden toothpick inserted in centres comes out clean. Cool in pans 10 minutes; remove to wire racks. Cool completely.
Meanwhile, beat sugar, cream cheese, butter and juice with electric mixer on low speed until well blended. Frost cupcakes.

Source: kraftfoods.com