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Overnight Sausage and Caramelized Onion Breakfast Casserole

Overnight Sausage and Caramelized Onion Breakfast Casserole

The ultimate comfort food, the Overnight Sausage and Caramelized Onion Breakfast Casserole is a cheesy, savory delight that’s perfect for gatherings. With layers of fluffy bread, rich sausage, and sweet caramelized onions, this dish will have everyone coming back for seconds. Make it tonight for an easy, satisfying breakfast that your family will love!
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Prep Time 25 minutes
Cook Time 40 minutes
Total Time 1 hour 5 minutes
Servings: 8 servings
Course: Breakfast
Cuisine: American
Calories: 400
Ingredients Equipment Method Notes

Ingredients
  

  • 1 pound breakfast sausage
  • 1 tablespoon vegetable oil
  • 1 tablespoon butter
  • 1 medium yellow or sweet onion thinly sliced
  • 1/2 each red bell pepper diced
  • 6 cups day old challah bread cubes
  • 6 large eggs
  • 1 1/4 cups half-and-half
  • 3/4 teaspoon salt
  • 1/2 teaspoon dry mustard
  • 1/2 teaspoon dried thyme
  • 1/8 teaspoon ground nutmeg
  • 1 cup shredded cheddar cheese
  • 1 cup shredded mozzarella cheese

Equipment

  • Oven
  • Baking Sheet
  • Skillet
  • Cutting Board
  • Whisk
  • Chef's Knife
  • Mixing Bowl

Method
 

  1. Start by cooking and crumbling the breakfast sausage in a large nonstick skillet over medium heat. This will take about 8 to 10 minutes. You want the sausage to develop a nice brown color while cooking. Once done, use a slotted spoon to remove the sausage from the skillet, leaving the drippings behind.
  2. Add vegetable oil and butter to the skillet with the drippings. Allow it to heat up before adding the onions. Cook the onions over medium heat for about 8 minutes, stirring occasionally, until they are soft and caramelized. This process is crucial because it develops the sweet flavor that complements the sausage.
  3. Next, add the diced red bell pepper to the onions and cook for another 5 minutes. Season the mixture with salt and pepper to taste. Once everything is well combined, transfer the mixture to the bowl with the sausage.
  4. In the meantime, preheat your oven to 350 degrees Fahrenheit. Grease a 7x11-inch baking dish to prevent sticking. Place the challah bread cubes in the bottom of the dish, spreading them evenly.
  5. Now, scatter the sausage and onion mixture on top of the bread cubes. This layering ensures that every bite has that delicious flavor combination.
  6. In a medium bowl, whisk together the eggs, half-and-half, salt, dry mustard, thyme, and nutmeg. This egg mixture is what binds everything together and gives the casserole its rich texture.
  7. Sprinkle half of the cheddar and mozzarella cheeses over the sausage mixture in the baking dish. This will create a delicious cheesy layer that melts beautifully.
  8. Pour the egg mixture evenly over the casserole, ensuring all the bread is soaked and the ingredients are distributed.
  9. Finally, sprinkle the remaining cheese on top. This will create a bubbly, golden crust as it bakes.
  10. Bake the casserole uncovered in the preheated oven for 40 minutes or until it is golden brown and set in the middle. You’ll know it’s done when a knife inserted comes out clean.

Notes

There are countless ways to customize your Overnight Sausage and Caramelized Onion Breakfast Casserole. Here are some tips to enhance your experience:
  • Storage: Store leftovers in an airtight container in the refrigerator for up to three days.
  • Freezing: You can freeze the unbaked casserole for up to three months. Just thaw in the fridge overnight before baking.
  • Pairing: Serve with fresh fruit or a light salad for a balanced meal.
  • Variations: Try adding spinach or mushrooms for a different flavor profile.
  • Cheese Swap: Experiment with different cheeses such as pepper jack for a spicy kick.
  • Make it Vegetarian: Substitute the sausage with a plant-based option for a vegetarian version.
  • Serving Size: This casserole can easily be halved if you're cooking for fewer people.