Place the tortellini, pepperoni slices, pizza sauce, oregano, vegetables, and 1 cup of the mozzarella cheese in a large resealable freezer bag.
Seal the top of the bag and shake to combine all the ingredients together. Reopen bag, remove excess air, and seal.
Put the other cup of cheese in a medium freezer bag. Seal and staple the small bag to the large bag above the seal.
Place in the freezer until you're ready to cook your casserole.
Cooking Instructions:
Transfer the ingredients to the refrigerator to thaw overnight.
Preheat the oven to 350°.
Pour the contents of large freezer bag into a casserole dish. Cover with the reserved mozzarella cheese.
Cover the casserole dish with foil and bake for 50 minutes. Then, remove the foil and bake an additional 10 minutes, until the cheese on top is melted.