The Only Make-Ahead Breakfast Casserole You’ll Want This Holiday Season (2024)

• 1 (10-ounce) package frozen chopped spinach, thawed and drained

• 1 tablespoon olive oil, plus more for greasing

• 1 medium yellow onion, chopped (about 1 cup)

• 3 clove garlic, finely chopped

• 1 (8-ounce) container mascarpone cheese (about 1 cup)

• 4 ounces Parmesan cheese, grated on a Microplane (about 1 cup), divided

• 2 teaspoons kosher salt, divided

• 1 teaspoon freshly ground black pepper, divided

• 10 large eggs

• 1 2/3 cups half-and-half

• 1/4 teaspoon crushed red pepper

• 6 English muffins, split

1. Prep the spinach:

   Place the spinach on a clean kitchen towel and squeeze firmly over the sink to remove as much liquid as possible. Set aside.

   

2. Cook the onion, garlic, and spinach:

   Heat the oil in a large skillet over medium-high heat. Add the onion and cook, stirring occasionally, until translucent, about 5 minutes. Add the garlic; cook, stirring often, until fragrant, about 30 seconds. Stir in the spinach; cook, stirring often and breaking up with a wooden spoon, until it looks dried out, about 2 minutes.

   Set aside to cool slightly, about 5 minutes.

   

3. Add the cheese and season:

   Reserve 1/4 cup of the spinach mixture. Transfer the remaining spinach mixture to a medium bowl and add mascarpone cheese, 1/2 cup of Parmesan, 1/2 teaspoon salt, and 1/2 teaspoon black pepper. Stir until well combined and set aside.

   

4. Assemble the casserole:

   Whisk the eggs, half-and-half, crushed red pepper, reserved 1/4 cup spinach mixture, 1/4 cup Parmesan, remaining 1 1/2 teaspoons salt, and 1/2 teaspoon black pepper in a large bowl until well combined.

   Lightly grease a 13x9-inch baking dish. Arrange the bottom halves of the English muffins in the dish in three rows of two. Evenly spread the spinach-mascarpone mixture over the muffins. Cover with the top English muffin halves. Pour the egg mixture over the casserole, then press down on the English muffins to submerge. Sprinkle with remaining 1/4 cup Parmesan.
   

   

   

   

5. Rest:

   Cover the dish with foil and refrigerate for at least 1 hour or up to 12 hours.

6. Bake and serve:

   Preheat the oven to 350°F. Uncover and bake the casserole in the preheated oven until just set and the tops of the English muffins are golden brown, about 45 minutes. Let the casserole cool 10 minutes before serving.

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Nutrition information is calculated using an ingredient database and should be considered an estimate. In cases where multiple ingredient alternatives are given, the first listed is calculated for nutrition. Garnishes and optional ingredients are not included.