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.
Step 2: Forming the Crust
Take your cookie dough, (if you have two kinds, here use whichever you have more of) and form it into a ball on a cutting board.
Now flatten the ball until it's a circle roughly an inch and a half tall.
Transfer it onto the cookie sheet directly in the middle of your powdered area.
Roll the the outside of the crust inward about an inch, then make an indent around the pizza about halfway into the dough, trying not to tear the pizza.
If you choose to use a pizza pan make sure to perforate (poke holes in) the crust. These don't have to be large, but they should be fairly numerous and are very important to make sure the cookie will bake properly.
Step 3: Sauce
Spread this on your pizza, inside the indent you made. A very thin layer will be enough, this is more for appearance and texture than taste.
If you have issues spreading the sauce you might consider using a clean finger to even out the edges.
Also, don't worry about getting a bit of sauce on the crust, we used to do that all the time in my pizzeria and no one seemed to mind.
Step 4: Cheese
For cheddar, all we need to do is mix about half a container of yellow food dye with our remaining white frosting.
For mozzarella, take half of the remaining frosting, and mix just a touch of yellow into it, then add more white until it is to your liking.
For Colby-Jack it's a bit more complicated; prepare half as cheddar and half as mozzarella or leave the other half white. The real challenge here is in applying the cheese, you should place short rectangles of alternating white and yellow cheeses in either a checker like or random pattern.
Now spread a thin layer, (not all of your cheese), of cheese across the pizza past the indent and on the very edge of the crust. Again, if you're having issue, consider using a cleaned finger to help. This helps to set the toppings as well as adds a bit to the appearance of the final product. We will add another layer after it bakes to add more of the taste.
Step 5: Toppings
Pepperoni: make a small circle out of your currently unused dough, coat this with red food dye until you are content with it's appearance and place it into the cheese on your pizza.
Green peppers: mix the cookie dough with green food dye and roll it into thin strips, curve these and place them lightly into your cheese.
Mushrooms: Mix red and green food dye with the dough until it looks like the colouration, of a mushroom. try your best to make it into the shape of a mushroom. Since that's next to impossible, you might need to cut it to shape when it's on the pizza.
Sausage: For these tear chunks of cookie dough into clumps and colour them the same as you would the mushroom. As before, place them lightly into the cheese.
Anchovies: I would suggest using Swedish fish for this.
If you would like an other toppings, let me know and I will try and make them for you.
Step 6: Baking and Final Cheese
Once the pizza is out of the oven let it cool for about 5 to 10 minutes or until you can apply frosting without it tearing up the center. You may need to add just a dab more food dye to the top of your toppings if they lost a bit of their colouration during baking.
Add a final layer of cheese in the style described before, let cool until the frosting can be cut and serve. Enjoy!