Preheat oven to 350 degrees F. Line 9”x9” baking tray with baking paper.

In large bowl, mix together all cake ingredients. Pour batter into prepared tray. Bake 20 minutes, until inside is cooked through.

Meanwhile, in large bowl, blend together frosting mix and shortening until smooth, adding water if needed. Mix in chlorophyll drops until frosting is an even, bright green. Transfer to plastic bag; cut corner off bag to pipe frosting.

On cutting board, cut cake into 14 evenly-sized triangles. Cut 7 straws in half horizontally. Insert a straw into base of each triangle.

Using frosting, create a zig zag pattern on each tree. Decorate with sprinkles.