In a large skillet over medium heat, sauté the chopped onion and minced garlic until fragrant and translucent, about 3-4 minutes.
Add the ground turkey or beef to the skillet, breaking it apart with a spatula. Cook until browned and fully cooked, about 8-10 minutes.
Stir in the diced bell peppers, cumin, paprika, salt, and pepper. Cook for an additional 5 minutes, until the peppers start to soften.
In a large mixing bowl, combine the quinoa, diced tomatoes (with juices), black beans, and corn. Add the cooked meat and vegetable mixture, stirring to combine.
Transfer the entire mixture into a greased 9x13 inch casserole dish, spreading it evenly.
Sprinkle the shredded cheese evenly over the top of the casserole.
Cover the dish with aluminum foil and bake for 30 minutes.
After 30 minutes, remove the foil and continue baking for an additional 10-15 minutes, until the cheese is bubbly and lightly golden.
Once cooked, remove the casserole from the oven and allow it to cool for a few minutes before serving.
Garnish with fresh cilantro or parsley if desired.
Notes
Garnish with fresh cilantro or parsley for added flavor.