The cottage cheese in this egg casserole may seem surprising but acts as an additional binder as well as additional protein source! If you don't enjoy cottage cheese, I don't think you'd notice it, but you can also skip the ingredient.
In a skillet on medium high heat, spray with cooking spray and add red onion, red pepper, garlic and pesto. Toss until soft and add spinach. Heat until wilted, stirring it all together. Transfer to a 9x13 casserole dish sprayed with cooking spray. Re-spray the skillet and brown the chicken sausage.
While chicken sausage is browning, whisk eggs and cottage cheese in a mixing bowl and set aside. Add sausage to baking dish and mix around with onion mixture.
Spread out mixture at the bottom of the casserole dish and pour in the egg mixture. Top with shredded cheese.
Bake in preheated oven for 30 minutes. Remove, let rest 5-10 minutes then cut and serve.