In a large bowl, mix together the Butter, Sugar, Brown Sugar, Egg, and Vanilla, until creamy and fluffy.
In a separate bowl, add the Flour, Salt, Baking Powder, and Baking Soda, and mix well. Add the Flour mixture to the Butter mixture a little at a time, stirring between additions, until all the flour has been incorporated and the mixture is like Cookie dough.
Add Sprinkles and M&M's to the bowl, and gently fold into the dough.
Grease and Flour the Cookie Pan, and press the Cookie Dough evenly into the pan, smoothing the top with the back of your spoon.
Bake at 350 for 20 minutes, then carefully remove to a wire rack to cool completely.
When cooled; add several drops of the Red Food Coloring Gel to the can of Frosting, until you get a bright Red color. Stir well to mix completely.
Place a large Star Tip in a Pastry bag, and place the Red Frosting in the Pastry bag. Pipe small Stars around the edge, and in the middle of the Cookie Cake.
Place an M&M in the center of the Frosting, and add more Sprinkles to the top of the Cookie Cake.
Serve, and ENJOY!