Prep. Preheat oven to 350 F and prepare an 8x8 casserole dish (I used an 8" round casserole dish) with cooking spray.
Saute veggies. Heat vegetable oil (1 tablespoon) in a large pan over medium heat. Add diced onions (1), diced bell peppers (1), and sliced mushrooms (3 cups). Cook until veggies are soft, and the liquid from the mushrooms has cooked off.
Assemble. Place veggies in the prepared casserole dish in an even layer. Pour whisked eggs (2) on top. Add cheese (1 cup), and stir to combine with veggies and eggs to form a "crust".
Cook beef. Add ground beef ( 2 Lbs ) to the pan and cook until no longer pink -- breaking the meat into small pieces as it cooks. Add tomato sauce, 1 (15 Ounce Can), garlic powder (2 teaspoons ), erythritol (2 tablespoons), and sriracha (1 teaspoon) to the pan and stir to combine. Bring the heat in the pan to a boil, then reduce to a simmer and cook for 5-7 minutes, or until hardly any liquid is left. It should look like a sloppy joe type consistency.
Assemble + Bake. Add meat to the casserole dish in an even layer. Sprinkle mozzarella (2 cups), then crushed pork rinds (2 cups ) on top. Bake in the oven for 20 minutes, or until the cheese has melted. Allow casserole to cool slightly before slicing. Enjoy!