Cheese and Spinach Strata

I made this dish for our Christmas morning breakfast this year and I was really happy with how it turned out. It's always nice to have something you can make ahead and then pop in the oven so you can enjoy Christmas morning instead of spending it in the kitchen. It lacked a bit of salt for my taste so I think next time I will add sausage (the husband likes meat) but it's great as a vegetarian option. You could add 1/2 cup more cheddar cheese for more flavor. Perfectly hearty as a stand alone dish. 

Prep time: 30 mins
Cook time: 45-55 mins
Serves: 6-8

INGREDIENTS:
3 tbsp unsalted butter
1 small onion, chopped
2 tsp garlic, minced (about 2 cloves)
Two 10-once packages of frozen spinach, thawed and drained
1 tsp salt, divided
1/2 tsp pepper, divided
8 cups ciabatta bread, cubed into 1-inch pieces (about 1 loaf)
6 ounces Gruyere, grated
1/2 cup sharp cheddar, grated
9 large eggs
2 3/4 cups milk

DIRECTIONS:
In a large saute pan over medium heat, melt butter.  Add the onions and cook until softened and translucent, about 5 minutes. Add the garlic, 1/2 teaspoon salt and 1/4 teaspoon of the pepper and cook for another minute. Add the spinach and cook until heated through, stirring, for about another 2 minutes or so. Set aside.

Generously spray a 2.5-quart baking dish with cooking spray. Combine the cheeses in a medium size bowl. Layer the bottom of the dish with about 1/3 of the bread cubes, top with 1/3 of the spinach, and 1/3 of the cheese mixture. Repeat the layering process two more times.

In a separate bowl, whisk together the eggs, milk, remaining salt and pepper until combined.  Evenly pour the egg mixture over the bread/cheese/spinach layers. Cover tightly and chill overnight.

Preheat the oven to 350 degrees. While your oven is preheating, let the strata come to room temperature. Bake uncovered until lightly crisped and golden, about 45-55 minutes.