Brown the sausage and break it into small pieces, drain and place on paper towels. Set aside.
Mix together prepared yellow mustard, eggs, milk, half and half, Worcestershire sauce, salt, and pepper, and whisk until combined. Set aside
Layers: place a layer of bread on the bottom of the prepared pan, top with 1/2 of the sausage, top that with 1/2 of the cheese, and top with 1/2 of the egg mixture. And then repeat layers.
To bake immediately-bake uncovered for 50 minutes to an hour or until set and serve immediately. It took about an hour and 10 minutes for me.
If you are planning to bake it the next day. Cover tightly and refrigerate overnight; take it out an hour before baking, bake uncovered for 50 minutes to an hour or until set, and serve immediately.
Notes
This is my family's go-to Christmas Breakfast. I have made it ahead of time and also made it the day of and it has turned out great.