Brown meats and vegetables:Heat a large skillet over medium-high heat. Brown the sausage and bacon. Add the onion, celery and red pepper and brown until softened. Place in a large bowl and cool for 5 minutes.
Prep: Preheat oven to 350°F. Lightly grease a 9x13 inch baking dish (OR use a very deep 7x11 dish for a thicker casserole).
Finish casserole:Add remaining ingredients to the bowl with the sausage mix. Stir well, then transfer to the prepared casserole dish.
Bake:Bake the casserole for 50-60 minutes, or until set in the middle. Cool for 10-15 minutes before slicing to serve.
Video
Notes
Ingredient notes
Sausage: Plain old breakfast sausage is the classic here, but feel free to use turkey breakfast sausage, maple breakfast sausage or even Italian sausage can all work in this casserole.
Red pepper: Feel free to use a yellow or green pepper in place of the red, if that’s all you have on hand.
Cheese: Shredded cheddar is my favorite here, but feel free to use Colby Jack, Gouda or Swiss cheese all work in place of the cheddar.
Milk: I find this casserole plenty rich, so I use 2% milk. Feel free to use whole or half and half instead. I would personally not use cream, because the casserole already has fat from the sausage, bacon and cheese.
Make ahead tips
You can bake the casserole ahead of time. Let it cool, then cover and refrigerate for up to 3 days.To reheat, simply put in a 375˚F oven for 30 minutes until the casserole is heated through.