Preheat your oven to 375°F (190°C). Lightly grease a 9×13 inch baking dish with cooking spray.

Place a large skillet over medium-high heat. Add the ground beef sausage and cook until fully browned, breaking it into small crumbles with a spatula. Drain any excess fat and set the meat aside.

In the same skillet, add the diced onions and bell peppers. Sauté for 4 to 5 minutes until the vegetables are tender and the onions are translucent. Stir in the chopped spinach at the very end just until it begins to wilt.

In a large mixing bowl, whisk together the eggs, liquid egg whites, cottage cheese, salt, pepper, garlic powder, and smoked paprika. Whisk vigorously to ensure the cottage cheese is well-incorporated.

Spread the cooked beef sausage and sautéed vegetable mixture evenly across the bottom of the prepared baking dish.

Sprinkle 1 cup of the shredded cheddar cheese over the meat and vegetables.

Pour the egg and cottage cheese mixture over the top, making sure it reaches all the corners of the dish.

Sprinkle the remaining 1/2 cup of cheddar cheese over the top for a golden finish.

Place the dish in the center rack of the oven and bake for 35 to 40 minutes. The casserole is done when the center is set and the top is lightly golden brown.

Remove from the oven and let it rest for 5 to 10 minutes before slicing into squares.