Heat a large non stick pan, when hot, add the bulk sausage, break it up with the your spatula, brown it until no more pink is visible. Drain well and set aside. If using bacon, fry that to crispy, drain on paper towels and crumble it up. If using cooked ham, cube that.
Preheat your oven to 180 C (350 F) and grease a 7x11 baking dish with butter or spray with an olive oil mister.
Tear up the bread into small pieces and place in the baking dish, spread them out evenly.
Spread the sausage, bacon, or ham, on the bread.
In a mixing bowl, whisk the eggs, then add the milk, mustard, salt, and pepper. Whisk until combined.
Pour the egg mixture over the sausage in the baking dish.
Sprinkle the cheese on top of the casserole.
Place in the oven uncovered and bake for 35 to 45 minutes or until set in the middle, check with a toothpick.
When done, remove from the oven, let the casserole rest 5 minutes. The casserole will be puffed up a bit, it will collapse down after 5 minutes.
Slice.
Serve and enjoy.