Preheat & Prep: Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish with butter or nonstick spray.
Cook the Sausage: In a large skillet over medium heat, cook the sausage until browned and fully cooked (about 5-7 minutes). Break it into crumbles as it cooks. Drain any excess grease and set aside.
Assemble the Casserole: Spread the cubed bread evenly in the greased baking dish. Sprinkle the cooked sausage over the bread. Add shredded cheese evenly over the top.
Make the Egg Mixture: In a large bowl, whisk together the eggs, milk, salt, pepper, garlic powder, onion powder, paprika, and dried mustard. Pour the egg mixture evenly over the sausage, bread, and cheese. Let it sit for 5 minutes to allow the bread to absorb the liquid.
Bake the Casserole: Cover with foil and bake for 30 minutes. Remove the foil and bake for another 10-15 minutes, until the top is golden brown and the eggs are set.
Serve & Enjoy!: Let the casserole rest for 5 minutes before slicing. Garnish with fresh parsley or green onions and serve warm.