1You can assemble this the night before and pop it in the oven to bake the next morning. However, I'm not that organized. I put it together in the morning and bake it as soon as it is done. Works just fine either way.
2Grease a 2 qt. casserole pan with butter.
3Trim crusts off bread. Cube slices and spread on shallow baking sheet. Bake or broil until cubes are dry, stir half way through so cubes are flipped over. I usually bake the bread cubes at 350 for about 10 min. You don't want croutons, just slightly dried out bread cubes.
4Brown crumbled sausage until thoroughly cooked. Drain off fat.
5Preheat oven to 325 degrees
6Place bread cubes evenly in bottom of baking dish.
7Sprinkle cheddar cheese on top of bread cubes. Add sausage on top.
8Mix salt, dry mustard, pepper and onion powder together (this helps to keep the mustard from getting lumpy).
9Add milk and spices to beaten eggs. Mix well.
10Gently pour mixture on top of meat, cheese, bread mixture.
11Bake uncovered for 1 hour. Cover with foil if the top gets too brown before center is done. (Test with toothpick or wooden skewer. It should come out clean.) Frittata will puff up in oven but sinks a bit when removed.
12Serve with salsa, green onions, peppers, sour cream, etc. Very good reheated for a quick snack or lunch.