Green Ombre Cake

Name: Green Ombre Cake
Prep time: 30 min
Cook time: 35 min
Yield: 12
Ingredients: 1 package (2-layer size) white cake mix; 2 tsps (10 ml) pure vanilla extract (club house); green food colour (club house); 1 cup (250 ml) (2 sticks) butter softened; 2 tsps (10 ml) pure vanilla extract (club house); 1 pound (500 g) icing sugar; 2 tbsps (30 ml) milk