In a large mixing bowl, combine black beans, corn, tomatoes, bell peppers, shredded cheese, salsa, cooked quinoa, cumin, chili powder, salt, and pepper.
Transfer the mixture to a greased baking dish.
Bake in the preheated oven for 25-30 minutes, until the casserole is heated through and the cheese is melted and bubbly.
Let it cool for a few minutes before serving. Enjoy!
Notes:
This casserole is great for meal prep and can be stored in the fridge for up to 4 days.