Preheat your oven to 350°F (175°C) and lightly grease a 9x13 inch baking dish with cooking spray or a little olive oil.
In a large pot, cook the whole wheat spaghetti according to package directions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium heat. Add minced garlic and sauté for about 1 minute until fragrant.
Add the ground turkey or chicken to the skillet. Cook until browned, about 5-7 minutes. Season with salt, pepper, and Italian seasoning.
Stir in the spinach, and cook until wilted (about 2-3 minutes for fresh or 1-2 minutes for frozen).
In a large mixing bowl, combine the cooked spaghetti, browned meat mixture, cottage cheese, diced tomatoes, and black beans. Fold in half of the mozzarella cheese. Mix thoroughly until evenly combined.
Transfer the mixture to the prepared baking dish and spread evenly.
Top with the remaining mozzarella cheese.
Cover the casserole with aluminum foil and bake for 25 minutes. Then, remove the foil and bake for an additional 10-15 minutes, until the cheese is bubbly and golden brown.
Once cooked, let the casserole cool for a few minutes before slicing. Garnish with fresh basil leaves, if desired.
Notes
Feel free to substitute ground turkey with chicken or a plant-based alternative.
Keyword casserole, healthy, high protein, spaghetti