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Martha Stewart Christmas Breakfast Casserole Recipe

Martha Stewart Christmas Breakfast Casserole

This make-ahead Martha Stewart Christmas Breakfast Casserole is the perfect way to ensure a relaxed and delicious holiday morning. The rich flavors of sausage, nutty Gruyère, and tangy sourdough meld together overnight, creating a luxurious and homey centerpiece for any brunch. It's an elegant, simple, and comforting dish that easily serves a crowd and fills the house with an incredible aroma.
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Prep Time 20 minutes
Cook Time 1 hour
Total Time 9 hours 20 minutes
Servings: 8 servings
Calories: 300
Ingredients Equipment Method Notes

Ingredients
  

Ingredients
  • 1 lb pork breakfast sausage
  • 1 large yellow onion, chopped
  • 1 (1-pound) loaf of sourdough bread, cut into 1-inch cubes (preferably a day or two old)
  • 2 cups shredded Gruyère cheese
  • 1/2 cup grated Parmesan cheese
  • 8 large eggs
  • 2 cups whole milk
  • 1 cup heavy cream
  • 1 tablespoon Dijon mustard
  • 1 teaspoon salt
  • 1/2 teaspoon black pepper
  • 1/4 teaspoon ground nutmeg

Equipment

  • Large skillet
  • Wooden spoon
  • Very large bowl
  • 9x13 inch baking dish
  • Whisk
  • Spatula
  • Plastic wrap or foil
  • Wire rack

Method
 

Instructions
  1. Brown the Sausage and Onion: In a large skillet over medium-high heat, cook the pork sausage and chopped onion. Use a wooden spoon to break the sausage into small crumbles as it cooks. Continue cooking until the sausage is thoroughly browned and the onion is soft and translucent, about 8-10 minutes. Drain off any excess grease from the pan and set the mixture aside.
  2. Layer the Casserole Base: In a very large bowl, combine the slightly stale sourdough bread cubes, the cooked sausage and onion mixture, the shredded Gruyère, and the grated Parmesan. Gently toss everything together until it's evenly distributed. Transfer this mixture into a 9x13-inch baking dish that you've greased with butter or nonstick spray. Spread it out into an even layer.
  3. Whisk the Egg Custard: In the same large bowl (no need to wash it!), whisk together the eggs, whole milk, heavy cream, Dijon mustard, salt, pepper, and ground nutmeg. Whisk vigorously until the mixture is smooth, completely combined, and slightly frothy.
  4. Pour and Chill Overnight: Carefully and evenly pour the egg custard over the bread and sausage mixture in the baking dish. Gently press down on the bread with a spatula to ensure the top layer gets saturated. Cover the dish tightly with plastic wrap or foil and refrigerate for at least 8 hours, but preferably overnight. This resting period is crucial for the bread to absorb the custard.
  5. Prepare for Baking: The next morning, preheat your oven to 350°F (175°C). Remove the casserole from the refrigerator and let it sit at room temperature for about 30 minutes. This helps take the chill off and promotes more even baking.
  6. Bake to Golden Perfection: Bake the casserole, uncovered, for 50 to 60 minutes. You'll know it's done when the top is beautifully golden brown and puffy, and the center is set (a knife inserted into the middle should come out clean). Let the casserole rest on a wire rack for at least 10 minutes before slicing and serving.

Notes

For best results, use day-old or slightly stale sourdough bread to prevent a mushy texture; you can toast fresh bread cubes lightly to dry them out. It is crucial to let the assembled casserole sit at room temperature for 30 minutes before baking to ensure it cooks evenly. The casserole is done when a knife inserted into the center comes out clean.