Start by preheating your oven to 325 degrees Fahrenheit. Grease a 9×13 inch baking dish to prevent sticking. Spread the bread evenly across the bottom of the dish. For optimal results, consider using a sturdier bread such as Pepperidge Farms Sourdough loaf.

Once the bread is in place, evenly sprinkle cooked sausage and shredded cheese over the bread. This layer should cover the bread completely to ensure even distribution of flavors.

In a large measuring cup, whisk together the eggs, milk, dry mustard, salt, and pepper until well combined. This mixture will serve as the binding agent and flavor enhancer for your casserole.

Pour the egg mixture evenly over the layered bread, sausage, and cheese in the pan. Cover the dish tightly and refrigerate overnight. This allows the bread to absorb the egg mixture, resulting in a more cohesive texture.

Place the casserole in the oven and bake for 45–55 minutes, depending on your preferred egg texture. Cover the dish loosely with foil for the first 30 minutes to prevent the top from over-browning, then remove the foil for the remaining baking time. To gauge doneness, insert a fork or knife into the center—cooking time may vary based on your oven and preferences regarding egg consistency.

Remove the casserole from the oven once fully baked, allowing it to cool slightly before serving. Enjoy this savory dish warm, perfect for breakfast or brunch gatherings.