1 (18.25 ounce) package yellow cake mix
1 (3 ounce) can frozen lemonade concentrate
1 (3 ounce) package instant lemon pudding mix
1 cup milk
1 (3.5 ounce) package instant lemon pudding mix
1/2 cup margarine
1/2 cup white sugar
1 teaspoon vanilla extract
Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan.
In a large bowl, mix together cake mix and lemonade concentrate. Mix lemonade concentrate with milk, lemon pudding mix, margarine, sugar and vanilla extract. Pour batter into prepared pan.
Bake in the preheated oven for 50 to 60 minutes, or until a toothpick inserted into the center of the cake comes out clean. Cool cake completely before icing. Frost with whipped frosting.