Spinach and Mushroom Breakfast Casserole
This Spinach and Mushroom Breakfast Casserole is a savory bread pudding that's perfect for brunch, meal prep, or holiday gatherings. Made with layers of day-old French bread, sautéed spinach, mushrooms, and onions, it’s topped with Swiss cheese and soaked in a flavorful custard of eggs, milk, and Dijon mustard. The casserole is prepared ahead of time, chilled overnight, and baked until golden and puffed. It’s a hearty, customizable, and stress-free dish that's as nutritious as it is delicious
Equipment
- 13 X 9 X 2 inch baking dish
- Mixing bowls one large for the custard mixture.
- Whisk for blending the eggs, milk, and seasonings.
- measuring cups and spoons
- Sillet for sauteing the vegetables.
- Spatula or wooden spoon for stirring the vegetables.
- Knife for chopping onions and mushrooms.
- cutting board
- Nonstick cooking spray for coating the baking dish and skillet.
- Plastic wrap or foil to cover the casserole while chilling.
- Oven preheated to 350℉ for baking.
- Cooling Rack for resting the casserole after baking.
Ingredients
Custard
- 5 large eggs
- 4 large egg whites
- 3 cups milk
- ¼ cup Dijon mustard
- Salt and pepper to taste
Bread Layer
- 1 16 oz loaf of day-old French bread, cut into 1-inch slices
Veggie Mixture
- ½ lb mushrooms sliced
- 1 tsp minced garlic
- 1 large onion chopped
- 2 10 oz boxes frozen chopped spinach, thawed and squeezed dry
- 1 tbsp flour
- Salt and pepper to taste
Topping
- 1 1/2 c Swiss cheese, shredded, divided
Instructions
Prepare the Custard
- In a large mixing bowl, whisk together the eggs, egg whites, milk, Dijon mustard, salt, and pepper. Set aside.
Layer the Bread
- Coat a 13x9x2-inch baking dish with nonstick cooking spray. Arrange half of the bread slices in the dish to create an even layer.
Sauté the Veggies
- Heat a skillet over medium heat and coat it with nonstick cooking spray. Sauté the mushrooms, garlic, and onion until they’re tender and aromatic. Add the thawed and squeezed spinach, then sprinkle in the flour. Stir to combine and cook for an additional 2 minutes. Season the mixture with salt and pepper to taste.
Assemble the Dish
- Spread the sautéed veggie mixture evenly over the bread layer in the baking dish. Sprinkle 1 cup of the shredded Swiss cheese over the veggies. Top with the remaining bread slices.
Add the Custard
- Pour the prepared egg mixture evenly over the casserole, ensuring all the bread is soaked. Gently press the bread down with a spatula to help it absorb the liquid. Cover the dish with plastic wrap and refrigerate for at least 2 hours, or overnight for the best flavor.
Bake
- Preheat your oven to 350°F (175°C). Remove the casserole from the refrigerator and let it sit at room temperature while the oven heats. Sprinkle the remaining ½ cup of Swiss cheese over the top. Bake uncovered for 40–50 minutes, or until the casserole is puffed and golden brown.
Serve and Enjoy
- Let the casserole cool for 5–10 minutes before slicing and serving. Pair it with a fresh fruit salad or a side of crispy bacon for the ultimate brunch spread!
Notes
The nutritional values provided are estimates only and are calculated based on general nutritional data for the listed ingredients. Actual values may vary depending on the specific brands, measurements, and preparation methods used. For precise dietary information, please consult a registered dietitian or use a verified nutrition calculator with the exact ingredients you use.
Nutrition
Calories: 280kcalCarbohydrates: 20gProtein: 16gFat: 14gSaturated Fat: 7gPolyunsaturated Fat: 1gMonounsaturated Fat: 4gCholesterol: 150mgSodium: 500mgPotassium: 400mgFiber: 3gSugar: 4gVitamin A: 5000IUVitamin C: 10mgCalcium: 250mgIron: 3mg
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