Preheat the oven to 350°F (175°C) and coat a baking dish with nonstick spray.

Cook the sausage by crumbling it into a skillet over medium heat. Sauté until browned, about 5-7 minutes.

Whisk together the eggs and milk in a bowl. Season with salt and pepper to taste.

Layer the bread cubes in the prepared baking dish. Top with the cooked sausage, fresh spinach, and half the shredded cheese.

Pour the egg mixture evenly over everything, allowing the bread to soak up all that goodness.

Sprinkle the remaining cheese on top and let the assembled strata sit for 15 minutes.

Bake for 40-45 minutes, or until the strata is set and the top is beautifully golden brown.

Let it rest for five minutes before serving.