Ingredients

• 1 tablespoon unsalted butter
• 8 ounce fresh mushrooms, sliced
• 10 ounce fresh spinach, roughly chopped
• 0.25 teaspoon salt
• 0.25 teaspoon black pepper
• 8 ounce crusty bread, cubed into 1-inch pieces
• 8 large eggs
• 2 cup whole milk
• 1.5 cup sharp cheddar cheese, shredded, shredded
• 0.5 teaspoon dry mustard powder
• 0.5 teaspoon garlic powder
• 2 tablespoon grated Parmesan cheese, grated
• 0.5 tablespoon unsalted butter

Steps

1. Grease a 9x13 inch baking dish with butter and set aside.
2. Melt 1 tablespoon butter in a large skillet over medium-high heat.
3. Add sliced mushrooms to the skillet and sauté for 5 minutes, stirring occasionally, until they release their moisture and begin to brown.
4. Add chopped spinach to the skillet and cook for 3 minutes, stirring frequently, until the spinach is wilted and any liquid has evaporated.
5. Season the vegetable mixture with 1/4 teaspoon salt and 1/4 teaspoon black pepper. Remove from heat and let cool slightly.
6. Distribute the cubed bread evenly across the bottom of the prepared baking dish.
7. Spread the cooked mushroom and spinach mixture evenly over the bread cubes.
8. In a large mixing bowl, whisk together 8 eggs, 2 cups whole milk, 1/2 teaspoon dry mustard powder, and 1/2 teaspoon garlic powder until well combined and smooth.
9. Pour the egg mixture evenly over the bread and vegetables in the baking dish.
10. Sprinkle 1 1/2 cups shredded sharp cheddar cheese evenly over the top of the casserole.
11. Top with 2 tablespoons grated Parmesan cheese for extra flavor and color.
12. Cover the baking dish tightly with plastic wrap or aluminum foil and refrigerate for at least 8 hours (or up to 24 hours) to allow the bread to absorb the egg mixture.
13. Remove the strata from the refrigerator and let it sit at room temperature for 15 minutes before baking.
14. Preheat your oven to 350°F (175°C).
15. Remove the plastic wrap or foil from the baking dish.
16. Bake uncovered for 50–55 minutes, until the top is golden brown, the casserole is puffed and set in the center, and a knife inserted near the center comes out clean or with just a few moist crumbs.
17. Remove the strata from the oven and let it rest for 10 minutes before slicing and serving.