Add the steel-cut oats, salsa (Salsano or similar no-sugar-added salsa), drained black beans, corn (if using), water, chili powder, cumin, salt, and black pepper to a medium pot or large skillet.
Bring the mixture to a boil over medium-high heat, then reduce to a low simmer. Cover and cook, stirring occasionally, for 25 minutes or until most of the liquid is absorbed and the oats are tender.
Turn off the heat and leave the covered pot on the burner for 5 minutes to finish steaming, then uncover and fluff gently with a fork.
To make quesadillas: spread 1/2 cup filling over a 6-inch whole-grain flour tortilla, sprinkle with 1/4 cup reduced-fat shredded cheddar, top with another tortilla, and bake at 400°F for 15 minutes; slice and serve hot.
To make burritos: place 1/4 cup filling in the center of a 6-inch flour tortilla, sprinkle with 1 tablespoon reduced-fat shredded cheddar, roll tightly, and fold under one end; add lettuce, tomato, and a dollop of Greek yogurt or sour cream if desired.
To make a casserole: add the cooked filling to a casserole pan, sprinkle with desired reduced-fat shredded cheddar, cover with foil, and bake at 375°F until cheese is melted and heated through, about 25 minutes.
To make burgers: cool the filling and refrigerate about 1 hour. Mash 1/2 cup filling in a bowl, stir in 2 tablespoons reduced-fat shredded cheddar and 2 tablespoons panko (add more panko if needed), form into patties, and cook in 1 tablespoon olive oil over medium heat about 4 minutes per side until browned and heated through.
To serve as a dip or nachos: use the filling warm as a dip or top whole-grain tortilla chips with filling, shredded cheddar, and jalapeños; bake nachos at 350°F for 10 minutes and top with sour cream or Greek yogurt before serving.
For enchiladas or Mexican pizza/breakfast pizza: follow the specific assembly and baking steps in the serving suggestions, using 1/4–1/2 cup filling per tortilla and baking at 375–400°F until heated through and cheese is melted.
