Prepare-Ahead Spinach and Mozzarella Breakfast Casserole

Ingredients

• 3 tablespoons unsalted butter
• 1 ½ cups finely chopped yellow onion
• 3 pinches herbes de Provence, or to taste
• salt and ground black pepper to taste
• 2 (10 ounce) packages frozen chopped spinach, thawed and drained
• butter-flavored cooking spray
• 8 cups cubed Italian bread
• 1 cup shredded reduced-fat mozzarella cheese, or more to taste
• 9 large eggs
• 1 cup skim milk

Step 1

Melt the butter in a medium skillet over medium heat. Toss in the onion and cook it until it’s nice and soft, about 5 minutes. Sprinkle in the herbes de Provence, salt, and pepper, and cook for another minute. Then stir in the spinach, take the pan off the heat, and set it aside.

Step 2

Spray a 9x13-inch baking dish with cooking spray. Begin by spreading a third of the bread cubes on the bottom, then add a layer of a third of the spinach mixture, followed by a third of the mozzarella. Repeat this layering two more times until everything’s used up.

Step 3

In a separate bowl, whisk together the eggs, milk, salt, and pepper until smooth. Pour this mixture evenly over the layered bread and spinach in the dish. Cover it with plastic wrap and pop it in the fridge for at least 8 hours, or up to a full day.

Step 4

When you’re ready to bake, take the casserole out of the fridge about 30 minutes beforehand to let it come to room temperature. Meanwhile, preheat your oven to 350°F (175°C).

Step 5

Bake the casserole uncovered for 45 to 55 minutes, until it’s puffed up and golden brown. Once it’s done, let it sit for at least 5 minutes before digging in.