Cube your bread into bite-sized chunks. If it's fresh, toast it at 350°F (175°C) for about 10 minutes to dry it out slightly.

In a skillet, heat olive oil over medium heat.

Sauté the onions and bell peppers until soft (about 5 minutes), then add the spinach and cook until just wilted.

Remove veggies and cook the Italian sausage in the same pan until browned and cooked through.

Lightly grease a 9x13-inch baking dish.

Add half of the bread cubes to the bottom.

Layer on half of the sausage and sautéed vegetables.

Sprinkle with half the mozzarella and Parmesan cheese.

Repeat the layers: bread, sausage and veggies, and cheeses.

In a large bowl, whisk together:

o Eggs

o Milk

o Garlic powder

o Dried oregano

o Crushed red pepper flakes (optional)

o A good pinch of salt and pepper

Pour the egg mixture evenly over the entire dish, gently pressing down with a spatula to help the bread absorb the liquid.

Cover tightly with foil or plastic wrap.

Refrigerate for at least 2 hours, or preferably overnight, to let everything soak and develop flavor.

Preheat oven to 350°F (175°C).

Remove the strata from the fridge and let it sit at room temperature for 20–30 minutes.

Bake uncovered for 45–55 minutes, or until the top is golden and the center is set (a knife inserted should come out clean).

Let rest for 10 minutes before slicing.