Grease a baking dish (I used 8x10) and preheat oven to 400 F. Mix 1 1/4 cups of the marinara sauce with the cauliflower rice and spread over the bottom of the baking dish.
Place a large skillet over medium heat. Add bacon to skillet and cook for 4-5 minutes on each side, until crispy. Remove and set aside.
Add squash to skillet and cook, stirring occasionally, for 9-10 minutes, until softened. Add bell pepper and onion and cook for 5-6 more minutes. Remove from skillet and set aside in a large bowl.
Add minced garlic, salt, and meat of choice to the skillet and cook for 7-8 minutes, until no longer pink. Add oregano, basil, and spinach. Stir to combine, and then add the meat to the bowl with the veggies. Add two eggs and mix thoroughly. Pour the meat and veggie mixture into the baking dish over the cauliflower rice.
Crumble bacon into chunky pieces and sprinkle over the top of the casserole. Add the remaining sauce in a few dollops on the top of the casserole. Bake for 50 mins to an hours, until the egg mixture is set.
Let cool for at least 10 mins before serving to allow the rice to set.