Put a medium cast-iron skillet in the oven and preheat the oven to 400 degrees F.
Bake the fries in the heated cast-iron skillet, mixing them a few times during the cooking process, until they are crisp, about 20 minutes.
Remove the skillet from the oven and top the fries with the pepperoni, sausage, sauce, peppers, mozzarella and Parmesan. You can also do layers of fries and toppings to make a pile of pizza fries. Return the skillet to the oven for 5 to 10 minutes to melt the cheese. Serve immediately with a side of pizza sauce for dipping.