From:  justapinch.com

Cook time: 30 Min Difficulty: EASY
Prep time: Serves: 15
INGREDIENTS
– 1 bx white cake mix (i use supermoist, by betty
crocker)
– 1 1/4 c water
– 1/3 c vegetable oil
– 2 tsp creme de menthe syrup or mint extract
– 3 egg whites
– 1/2 c sour cream
– 12 drops of green food coloring
– 2 jar(s) (16 ounce each) hot fudge topping
– 1 8 ounce container of cool whip
– 5 drops yellow food coloring
– 1 bx creme de menthe chocolate candies, unwrapped and
cut into pieces….(andes mints)
DIRECTIONS

1.   Heat oven to 350 degrees, If using a dark or nonstick pan…heat oven to 325. Spray bottom ONLY of 13×9-inch pan with baking spray with flour.

2.   Make cake mix as directed on box, using water, oil, 1 1/2 teaspoons of the creme de menth syrup or mint extract, and egg whites. After mixing for one minute on low, then add sour cream, and mix another minute on medium speed. Reserve 1 cup batter. Stir in 3 drops of the green food color into reserved batter; set aside. Pour remaining white batter into pan.

3.   Drop green batter by generous tablespoonfuls randomly in 12 to 15 mounds onto batter in pan. Cut through batter with metal spatula or knife in S-shaped curves in one continuous motion. Turn pan 1/4 turn; repeat cutting for swirled design.

4.   Bake 28 to 33 minutes or until toothpick inserted in center comes out clean. Watch carefully so not to overbake! Run knife around the side of pan to loosen cake. Cool completely, about 1 hour.

5.   Carefully spread fudge topping evenly over cake. In medium bowl, stir whipped topping with 1/2 teaspoon of creme de menth syrup or mint extract along with the remaining 9 drops of green food color along with the yellow food color until blended. Spread whipped topping mixture evenly over fudge. Garnish with candy pieces. Store covered in refrigerator. If desired..you can use REAL whipping cream..whip the cream until it comes to stiff peaks..then add remaining mint extract along with food coloring and frost cake and add andes mints on top.