Overnight Omelette Breakfast Casserole

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Overnight Omelette Breakfast Casserole is a perfect make ahead meal.  It’s loaded with sausage, bacon, veggies, eggs, and cheese, and will be on your meal rotation all year long!

We love our breakfast casseroles, and others on the blog include Sausage Hash Brown Breakfast Casserole and Blueberry French Toast Casserole. For a simple quesadilla, try my Veggie Omelette Quesadillas too!

Side shot of a square of omelette casserole being lifted up over the casserole.

Omelette Breakfast Casserole

If ya’ll have ever made omelettes for a group, and realized that all you did was cook while everybody else was eating, this casserole is for you. Make a mess in your kitchen the day before, and then keep it stress-free at meal time. That’s what I’m talking about.

  • You simply make it the night before your breakfast.
  • Store it in the refrigerator overnight.
  • And then pop it in the oven about an hour before you eat.

This omelette casserole tastes like the real thing. You won’t be disappointed. I promise!

Close up shot of a corner of an omelette casserole.

Ingredients needed for Overnight Omelette Breakfast Casserole:

  • Sausage – Use mild, sweet, or spicy Italian sausage – according to what you like best.
  • Bacon – You’ll need about 6 slices of bacon, sliced in strips.
  • Olive Oil – Used to sauté the veggies.
  • Veggies – Onion, garlic, red bell pepper, mushrooms, and spinach. You could also use additional veggies, if desired.
  • Eggs – A dozen large eggs.
  • Milk – I use 2%, but use whatever you have on hand.
  • Spices – Ground mustard, kosher salt, and freshly ground black pepper.
  • Sliced Bread – Crusts removed.
  • Butter – Used to butter one side of the bread.
  • Cheese – One cup (or two) of shredded cheddar cheese works (and tastes) great!
Overhead shot of a cast iron skillet with cooked veggies.
Overhead shot of a cast iron skillet with cooked sausage and bacon.
Overhead shot of a glass bowl of whisked egg and milk, with a wire whisk.

How to make Overnight Omelette Breakfast Casserole:

  1. Cook the sausage. In a skillet, brown the sausage until full cooked. Spoon into a colander to strain.
  2. Cook the bacon. In the same skillet, cook the sliced bacon until crispy. Add to the colander, and remove grease.
  3. Sauté the veggies. Using the same skillet, sauté the onion and bell pepper for a few minutes. Then add the garlic, mushrooms, and spinach, and cook for another couple of minutes. Set aside.
  4. Make the egg mixture. To a mixing bowl, add the eggs, milk, ground mustard, salt, and pepper. Whip until very well mixed.
  5. Prep bread. Remove the crusts from the sliced bread, and butter one side.
  6. Assemble. Place the bread in the casserole dish, butter side down. Add the sausage and bacon, then the sautéed veggies, the egg mixture, and top with shredded cheese.
  7. Refrigerate. Cover casserole with Saran Wrap and place in the refrigerator overnight. You can also make this immediately.
  8. Bake. Bake in a preheated 375 degree oven for approximately 45 minutes, or until eggs are set in the middle.
  9. EAT.

Other Overnight Breakfast Dishes you should try next:


Side shot of a layer of omelette breakfast casserole.

Make this breakfast recipe next: Creamy Vegetable Frittata

Please let know if you try this recipe. Be sure to comment and leave a review on the blog so I can see what you think. You can also like my Facebook Page, follow me on Pinterest, and catch me on Instagram.

xoxo ~Sue

Side shot of a square of omelette casserole being lifted up over the casserole.

Overnight Omelette Breakfast Casserole

Overnight Omelette Breakfast Casserole is a perfect make ahead meal.  It's loaded with sausage, bacon, veggies, eggs, and cheese, and will be on your meal rotation all year long!
5 from 4 votes
Print Pin Rate
Course: Breakfast
Cuisine: American
Prep Time: 30 minutes
Cook Time: 45 minutes
Total Time: 1 hour 15 minutes
Servings: 10 people
Calories: 435kcal
Author: Sue Ringsdorf


  • 7 slices old bread
  • 1 Tablespoons butter – or enough to spread on bread
  • 1 pound sausage – cooked and crumbled
  • 6 strips bacon – cooked and crumbled
  • 12 large eggs
  • 1 cup 2% milk – or use whatever milk you have
  • 1 Tablespoons olive oil
  • 1 1/2 cups spinach leaves
  • 1 cup sliced mushrooms
  • 1/2 large onion – diced
  • 1 medium red bell pepper – diced
  • 2 cloves garlic – minced
  • 1 cup shredded cheddar cheese – or use more
  • 1 teaspoon dry mustard
  • kosher salt and freshly ground black pepper – to taste


  • In skillet, cook sausage till done. Drain fat and set aside.
  • Cut bacon in small strips. Cook in skillet (you can use same one as sausage) till nicely browned. Set cooked bacon on paper towel to soak up some of the fat.
  • In 1 tablespoons of olive oil, saute onion, garlic, red pepper, mushrooms, and spinach. Season with salt and pepper and cook until soft.
  • In mixing bowl, whip eggs, milk, ground mustard, salt and pepper (to taste). Set aside.
  • Remove the crust from the slices of bread. Butter one side and put that side down in casserole dish.
  • Spoon sausage and bacon on bread layer. Then top with cooked veggies and then egg mixture. Top with the shredded cheese.
  • Cover tightly with saran wrap and refrigerate overnight.
  • In the morning, cook the casserole on 375, uncovered, for approximately 45 minutes, or until the eggs are cooked and the breakfast casserole is nice and golden brown on top.



  1. Use your choice of meat for this casserole. You can even skip it for a meatless dish.
  2. The veggies can be substituted as well, for whatever you like best.
  3. Baking time will vary according to your oven, but the eggs should be set in the middle before serving.
  4. The leftovers are great too, for up to three days.


Calories: 435kcal | Carbohydrates: 14g | Protein: 23g | Fat: 31g | Saturated Fat: 12g | Cholesterol: 311mg | Sodium: 670mg | Potassium: 404mg | Fiber: 1g | Sugar: 4g | Vitamin A: 1368IU | Vitamin C: 18mg | Calcium: 186mg | Iron: 3mg
Tried this recipe?Mention @Suebeehomemaker or tag #suebeehomemaker!


  1. Lisa Tittle says:

    Oh my Goodness!! I have to rave about this dish! First off, it’s easy to put together and second, it’s soooo flavorful! I’ve made this casserole several different times – with different flavored sausages, some with and some without bacon. I’ve tried different types of mushrooms and with both regular bell peppers and a combo of bell and fresh jalapenos. Every combination I’ve thrown together has been marvelous. I love being able to incorporate healthy vegetables and savoring their flavors, without them dominating the whole dish. I’ve stuck to your proportions because it all works together so well. I’ve made this and shared with friends and family. Leftovers the second and third day are just as good. Always a hit!! Thank you Sue!

    1. Suebee Homemaker says:

      Thanks so much, Lisa! 🙂

  2. Is this something I can cook and take by a friend for breakfast? Does it travel and reheat well?

    1. Suebee Homemaker says:

      Definitely. I would recommend heating one piece at a time instead of the whole casserole, however.

  3. Can you make this the night before? It looks great. What other veggies work in place of mushrooms? Thanks!

    1. Suebee Homemaker says:

      Yes, this is a casserole you can place in the refrigerator overnight and bake in the morning. You can just leave the mushrooms out and add more of the other veggies. Good luck!

  4. Love this casserole! I had to feed a group of friends that included two requiring gluten free and one that could not have beef or pork. I used gluten free bread, turkey sausage and turkey bacon. It received rave reviews and everyone wanted seconds! Thank you Sue for another 5 star recipe!

    1. Suebee Homemaker says:

      Oh, that’s so awesome, Vicki! I really appreciate your sweet comments!

  5. If you love breakfast food, than this recipe is for you! I know most will enjoy at breakfast, but it makes a great weekend brunch or lunch option!

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