Creating the Overnight Breakfast Casserole is a straightforward process if you follow these steps:

1. Sauté the sausage: In a skillet over medium heat, brown the sausage until fully cooked. Drain excess fat and remove from heat.
2. Whisk eggs and milk: In a large mixing bowl, whisk together the eggs, milk, salt, pepper, garlic powder, and onion powder until well combined.
3. Prepare the bread: Add the cubed bread to the egg mixture, ensuring that each piece is soaked. Allow it to soak for a few minutes.
4. Combine ingredients: Gently fold in the cooked sausage, shredded cheese, and optional vegetables.
5. Transfer to baking dish: Pour the entire mixture into a greased 9×13-inch baking dish, spreading it evenly.
6. Cover and refrigerate: Cover the dish with plastic wrap and place it in the refrigerator overnight, allowing the flavors to meld.
7. Preheat the oven: In the morning, preheat your oven to 350°F (175°C).
8. Bake the casserole: Remove the plastic wrap and bake for 45-50 minutes, or until the center is set and the top is golden brown.
9. Cool slightly: Allow the casserole to cool for about 5 minutes before cutting into squares.

These steps will lead you to create a mouthwatering Overnight Breakfast Casserole that will impress everyone.