Preheat your oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish with olive oil spray.

In a large skillet over medium heat, cook the turkey sausage for 10-12 minutes, breaking it into crumbles until fully browned. Drain any excess fat and let cool for 2-3 minutes.

In a large mixing bowl, whisk the eggs vigorously until light and frothy. Add cottage cheese, chopped spinach, diced bell pepper, chopped onion, and shredded cheddar cheese. Stir until evenly distributed.

Fold in the cooled turkey sausage and season with salt and pepper. Mix until combined.

Pour the mixture into the prepared baking dish, spreading evenly to the corners.

Bake for 30-35 minutes or until the center no longer jiggles and a knife inserted in the center comes out clean. The top should be golden brown.

Let the casserole rest for 5 minutes before cutting into squares. Serve warm.