Choose:

 - 1 meat

 - 1 carb (2, if adding beans)

 - some vegetables

 -  sauce

 -  seasonings

Optional:

 - eggs

 - cheese

Cook meats, hearty vegetables, and dense carbs before combining in the 9x13. Cover with foil if drying out could be a concern. Bake for 25-40 minutes, uncover for the last 10 minutes of cook time for a crispier top.

Meats:

 - ground beef or sausage

 - shredded or diced chicken or turkey

 - pepperoni or summer sausage

 - tuna

Carbs:

 - rice

 - pasta

 - potatoes

 - tortillas, flour or corn

 - bread or stuffing mix

 - beans

Vegetables:

 - onions

 - green peppers

 - mushrooms

 - broccoli

 - zucchini

 - carrots

 - corn

 - peas

 - green beans

 - spinach

 - tomatoes

 - olives

Sauces:

 - white (with or without cheese)

 - enchilada

 - gravy

 - tomato-based

 - Alfredo

Seasonings:

 - Mexican (taco seasoning, cumin, chili powder, paprika, cayenne pepper, hot sauce)

 - Italian (oregano, basil, thyme, parsley, rosemary, or pre-blended as Italian seasoning)

 - savory (garlic powder, onion powder, salt, pepper, soy sauce, Worcestershire sauce, papika)