Turkey Spinach Sweet Potato Breakfast Casserole

Name: Turkey Spinach Sweet Potato Breakfast Casserole
Prep time: 15 min
Cook time: 50 min
Total time: 1 h 5 min
Cuisine: American
Ingredients: cooking spray; 1 tablespoon vegetable oil, or to taste; 1 pound turkey sausage; 2 cups fresh spinach; 12 egg whites; 0.25 cup almond milk; 0.75 teaspoon dried sage; 0.25 teaspoon dried thyme; 0.25 teaspoon dried oregano; 0.25 teaspoon red pepper flakes; 0.25 teaspoon dried basil; 1 pinch ground nutmeg; salt and ground black pepper to taste; 2 cups peeled and grated sweet potatoes; 1 tablespoon grated Parmesan cheese