Stuffed shells is a classic dish from Italian-American red sauce joints. Unfortunately, it's pretty easy to mess up. From shells that get too crispy in the oven to a stuffing that's too dry, there are a number of ways that this dish can go from "wow" to "ho-hum." But the recipe below overcomes all of these issues and more.
To start, you'll need a homemade marinara sauce with a rich flavor. Then you combine ricotta, mozzarella, cottage cheese and rich ground beef and stuff the mixture into the shells. Finally, bake the casserole covered until the very end, so that it doesn't dry out.
Italian Stuffed Shells Casserole 
Ingredients2 tablespoons olive oil, divided
1 onion, small diced
3 garlic cloves, minced
1 teaspoon red chili flakes
1 tablespoon tomato paste
1 32-ounce can whole, peeled tomatoes
1 teaspoon dried basil
1 pound ground beef
1 cup cottage cheese
1 cup ricotta
2 cups shredded mozzarella cheese
½ cup shredded Parmesan cheese
18-24 jumbo shell noodles, cooked and drained
Salt and pepper to taste
Directions1. Preheat the oven to 350 degrees Fahrenheit.
2. Heat 1 tablespoon olive oil in a heavy-bottomed pot. Add the onion and season with salt and pepper. Cook until slightly browned, about 10 minutes.
3. Add the garlic and chili flakes. Cook until translucent, about 1 minute.
4. Add the tomato paste and fry for 1 minute. Add the tomatoes and basil. Simmer for 20 minutes.
5. Meanwhile, cook the ground beef in a skillet in the other tablespoon of olive oil. Season with salt and pepper and set aside to cool.
6. Use an immersion blender or a regular blender to puree the tomato sauce until smooth.
7. Combine the cooled beef, cottage cheese, ricotta, half the mozzarella and Parmesan.
8. Spread a thin layer of tomato sauce in the base of a casserole dish. Stuff each of the shells with the beef mixture, and then line up in the dish. Top with a generous layer of tomato sauce and the remaining mozzarella.
9. Cover with foil and bake for 15 minutes. Remove the foil and continue baking until the top is slightly browned.
