Preheat your oven to 350°F (175°C). Grease a 9x13 baking dish.
Crumble the cornbread into the prepared baking dish.
In a large bowl, whisk together the eggs, milk, salt, and pepper. Optionally, add maple syrup, smoked paprika, or fresh herbs for extra flavor.
Cook and crumble the breakfast sausage (or your chosen protein) in a skillet over medium heat. Drain any excess fat.
Evenly distribute the cooked sausage over the cornbread in the baking dish.
Pour the egg mixture over the cornbread and sausage, ensuring everything is well coated.
Sprinkle the shredded cheese evenly over the top.
Let the casserole soak for 15 minutes if baking the same day. For make-ahead, cover and refrigerate overnight.
Bake for 40-45 minutes until the center is set and the top is golden brown. If the center is still jiggly, cover with foil and continue baking.
Let cool for 5-10 minutes before serving.