You have two options for the main ingredient, cookie dough, while I recommend making the dough from scratch, I also understand that not everyone has time or feels comfortable with this. If you would rather use store bought dough you can skip the first few steps to get to the pizza part.
Also, You can use either a pizza pan or a cookie sheet for the baking. When selecting your cookie sheet make sure to consider how large cookie dough gets when it bakes. You'll see in the pictures that I didn't do so well at that.
For the pizza you will need:
A good amount of cookie dough; we used about a batch and a half
A can of frosting
For the dough you will need: (via Allrecipes.com)
2 and 3/4 cups of flour
1 teaspoon baking soda
1/2 teaspoon baking powder
1 cup of butter
1 1/2 cups white sugar
1 teaspoon vanilla extract
Step 1: Making the crust
In a small bowl, stir together flour, baking soda, and baking powder.
In a large bowl, cream together the butter and sugar until smooth. Beat in egg and vanilla. Gradually blend in the dry ingredients.
You might want to let this set a bit before continuing, at least until it isn't quite so moist and is more workable.