Cook the sausage in a big pan.
Break it into small pieces while cooking.
Cook until it turns brown completely.
Drain the extra grease from sausage.
Let it cool for few minutes.
Cut bread slices into small cubes.
Grease your baking dish with butter.
Spread bread cubes evenly in dish.
The bread forms the casserole base.
Sprinkle cooked sausage over bread cubes.
Add shredded cheese on top evenly.
Make sure everything spreads out nicely.
This creates delicious layers of flavor.
Crack eggs into your mixing bowl.
Add milk to the eggs now.
Put in mustard powder and salt.
Add black pepper to the mixture.
Whisk everything together until smooth.
Make sure it's well combined.
Pour egg mixture over bread and sausage.
Press down gently with a spoon.
This helps bread soak up mixture.
Cover dish with aluminum foil tightly.
Put it in the fridge overnight.
Preheat your oven to 350 degrees.
Take casserole out of the fridge.
Let it sit for 30 minutes.
Bake covered for 45 minutes first.
Remove foil and bake 15 minutes.
The top should turn golden brown.