Bake cake. Prepare cake batter following recipe instructions. Bake and cool two cake layers.
Level both cake layers. Place the first cake layer onto the turntable. Using white frosting, and spatula, frost cake layer and spread evenly. Stack the second layer of cake on top of the first layer then add frosting and spread evenly.
Frost Cake. Spatula ice cake smooth using white icing.
To form ribbons on the sides of the cake, place the tip of the spatula on the bottom side of the cake. Carefully move the tip of the spatula up as the cake spins on the turntable. Continue until the sides of the cake are complete.
Tint icing. Tint 1/2 cup icing light green, and 1/4 cup icing chartreuse using color combinations provided.
Combine Moss Green and Lemon Yellow icing colors to get chartreuse color shown.
Combine Leaf Green and Sky Blue icing colors to get a light green color shown.
Using Kelly Green icing color, tint 1/2 cup icing dark green. Reserve 1/8 cup of white icing.
Prepare decorating bags. Prepare a decorating bag with tip 21 and dark green icing. Prepare a second decorating bag with tip 32 and light green icing. Prepare a third decorating bag with tip 1M and chartreuse icing.
Decorate cake. Using each bag prepared with colored icing, pipe swirls on top of the cake, resembling trees. Next, sprinkle trees with white nonpareils.
Piping a tree is similar to piping a swirl. To create a tree shape, start with a narrow base, piping almost directly on top of the previous rotation to build a cone shape.
Prepare a decorating bag with tip 3 and the reserved white icing. Pipe dots around the sides of the cake.