Directions

• Preheat oven to 375 degrees F.
• In a 12-inch skillet, add sausage, cook, occasionally stirring, until the sausage is browned and crumbly. 
• Remove the sausage using a slotted spoon, reserving drippings in the skillet.
• Add the squash, mushrooms, onion, garlic, salt, 1 teaspoon Italian seasoning, crushed red pepper, and black pepper to the skillet. 
• Cook over medium heat, occasionally stirring, until vegetables are tender.
• Stir in sausage, marinara sauce, and spinach; cook occasionally, stirring, until heated through.
• Reserve 5 cups of meat sauce from the skillet. 
• In a 5-quart Dutch oven, pour the remaining sauce into the bottom.  Spread half of the tortellini on top of the meat sauce.  Spread 1-1/2 cups of meat sauce over the top of the tortellini.
• In a medium bowl, whisk together ricotta, Parmesan, egg, and the remaining 1/4 teaspoon of Italian seasoning.  Spread ricotta mixture over the sauce in the Dutch oven.  Sprinkle half of the mozzarella cheese over the ricotta.
• Spread 1-1/2 cups of meat sauce onto the mozzarella cheese.  Top with remaining tortellini and then remaining meat sauce.
• Loosely cover the Dutch oven with foil and bake for 1 hour.  15 minutes before the dish is done cooking, remove the foil and top with the remaining mozzarella cheese.
• Let stand for at least 15 minutes before serving.