Crumble sausage into a large skillet, season with minced onions and Italian seasoning, and cook until brown and slightly crisp
Drain sausage on a paper towel-lined plate, and set aside
In a large mixing bowl, whisk the eggs, milk, salt and pepper together
Place the cut bread evenly in a lightly greased 9 x 13-inch baking dish or casserole dish, and top with sausage and shredded cheese
Pour egg mixture evenly over the top, cover with plastic wrap, and refrigerate overnight
The next morning, take casserole out of fridge, remove cover, and pre heat oven to 350℉
Bake for 45 minutes or until golden brown and heated through. Internal temperature should be at least 160℉
Remove from oven, and allow to rest for 5 minutes before slicing