I saw this recipe and made it the next day -- it was a real treat for us because we all love the taste of lemons and it has a nice creamy frosting. They were so good they only lasted one day in our house!
Preheat oven to 350 degrees. Beat cake mix with water, egg whites and oil. Add dry pudding mix and beat in a 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 tins.
Bake 21-24 minutes or until wooden toothpick inserted in centers comes out clean. Cool in pans 10 minutes; remove to wire racks. Cool completely.
Meanwhile, beat sugar, cream cheese, butter and lemon juice with electric mixer on low speed until well blended. Frost cupcakes.