1 box white cake mix
1 (12 oz) can of root beer
1/4 cup vegetable oil
3 egg whites
1 teaspoon root beer concentrate OR 1 Tablespoon root beer flavored syrup
1 container (16 oz) vanilla frosting
about 10 root beer barrel candies, crushed
350 degree oven. Spray bottom only of 9 x13 pan with cooking spray with flour.
In large bowl, beat cake mix, root beer , oil, and egg whites on low for 30 seconds. Beat on medium for 2 minutes. Pour in pan, bake 28 to 36 minutes or until toothpick inserted in center comes out clean. Cool completely, about an hour.
Stir root beer concentrate in frosting. Spread on cake.
Just before serving, sprinkle crushed candies on top. (Candies will start to melt if sprinkled on frosting for loner than 1 - 3 hours.)