Mushroom, Sausage, and Spinach Strata

Name: Mushroom, Sausage, and Spinach Strata
Cuisine: American
Ingredients: 4 ounces of a crusty baguette, cut into 1/2 inch cubes; 8 ounces of hot Italian sausage, casings removed; 1 tablespoon unsalted butter; 1 medium yellow or brown onion, halved and thinly sliced; 4 ounces cremini mushrooms, stemmed and coarsely chopped; 2 large cloves of garlic, minced; 2 teaspoons of chopped fresh thyme; Salt and freshly ground black pepper; 4 ounces baby spinach (about 4 cups); 4 large eggs; 1 cup whole milk; 3 ounces smoked Gouda cheese, grated (about 3/4 cup)