1. Prepare the Bread Base

Start by cutting your day-old bread into cubes. If you’re using French bread or brioche, the cubes should be about 1-2 inches in size. Day-old bread works best because it holds its shape when soaked in the egg mixture, whereas fresh bread may get too soggy. You can also lightly toast the bread cubes in the oven at 350°F (175°C) for 10-15 minutes to give them a bit of a firmer texture.

Place the cubed bread evenly in a greased 9×13-inch baking dish. If you prefer, you can also use a casserole dish that’s slightly smaller or larger, but the cooking time may vary slightly depending on the size and depth of the dish.

2. Cook the Sausage

In a large skillet, cook the breakfast sausage over medium heat, breaking it apart with a spatula into small crumbles as it cooks. Continue cooking for 8-10 minutes, until the sausage is fully browned and cooked through. If you’re using bacon or ham, cook the bacon until crispy, then chop it into small pieces.

After cooking, drain off any excess fat from the sausage and set the meat aside to cool for a few minutes. This step is important because it ensures the casserole won’t be greasy, and it helps the sausage flavors settle before adding it to the casserole.

3. Prepare the Egg Mixture

In a large bowl, whisk together the eggs, milk, salt, pepper, garlic powder, and onion powder. Whisk thoroughly until everything is well combined. This egg mixture will be poured over the bread and sausage, so make sure it’s well seasoned. For added flavor, you can include a teaspoon of Dijon mustard or a pinch of cayenne pepper for some heat.

If you’re using any other seasonings or herbs, like thyme or rosemary, now is the time to add them. The egg mixture serves as the base that binds the casserole together, so make sure it’s seasoned to your liking.

4. Assemble the Casserole

Once the bread cubes are evenly placed in the baking dish, layer the cooked sausage (or bacon/ham) over the bread. If you’re adding vegetables, such as diced bell peppers, onions, or spinach, sprinkle them evenly over the meat layer. You can mix in other veggies like mushrooms, zucchini, or tomatoes if you prefer.

Once the bread, sausage, and vegetables are arranged, pour the prepared egg mixture evenly over the entire casserole. Gently press down on the bread and other ingredients to help them soak up the egg mixture. This step ensures that all the bread gets coated and the casserole comes out nice and fluffy.

5. Refrigerate Overnight

After assembling the casserole, cover it tightly with plastic wrap or aluminum foil and place it in the refrigerator overnight. This resting time allows the bread to soak up the egg mixture and absorb the flavors. If you’re short on time, you can let it sit for a minimum of 2 hours, but overnight is ideal for the best texture.

6. Bake the Casserole

The next morning, preheat your oven to 350°F (175°C). Remove the casserole from the refrigerator and let it sit at room temperature for 10-15 minutes before baking. This helps it bake more evenly. If desired, sprinkle the shredded mozzarella cheese over the top of the casserole for a gooey, cheesy crust.

Bake the casserole for 35-45 minutes, or until the eggs are set and the top is golden brown. You can check for doneness by inserting a knife or toothpick into the center of the casserole. If it comes out clean, your casserole is ready to be served.

7. Garnish and Serve

Once the casserole is done baking, remove it from the oven and let it cool for about 5 minutes before serving. Garnish with freshly chopped parsley or chives for a fresh, colorful touch. Slice the casserole into squares and serve warm.