Preheat oven to 325°F. Line a 12-inch pizza pan with parchment paper.
Press the cookie dough into the prepared pan and bake until golden brown and set, 15 to 18 minutes. Cool completely. Set aside 1/4 cup white frosting and tint green Divide remaining equally. Tint one portion blue and leave the other white. Frost cookie and decorate with candies. Slice into wedges to serve.
Do you want to take a stab at decorating this like a snow globe?