Preheat oven to 350°F. Spray a 9x13-inch baking dish with nonstick spray. Set aside.
In a large skillet set over medium-high heat, brown the ground beef until it is no longer pink. Use a slotted spoon to transfer the cooked beef to a paper towel-lined bowl.
1 pound ground beef
Add the onion and bell pepper to the skillet and sauté in the leftover fat for 2-3 minutes. Add the garlic and cook for 30 seconds.
½ cup diced onion, ½ cup diced bell pepper, 2 cloves garlic
Return the beef to the skillet. Stir in the drained tomatoes, tomato paste, salt, Italian seasoning, pepper, and Worcestershire sauce. Bring the mixture to a boil, reduce the heat, and simmer for 5 minutes. Remove from the heat and set aside.
14.5 ounces diced tomatoes, 2 tablespoons tomato paste, 1 teaspoon kosher salt, 1 teaspoon Italian seasoning, ½ teaspoon ground black pepper, 1 teaspoon Worcestershire sauce
Meanwhile, boil the noodles according to package instructions, drain, and transfer to a large bowl.
8 ounces dry shell pasta
Add the softened cream cheese, sour cream, and melted butter to the pasta. Mix well until the pasta is coated.
8 ounces cream cheese, ½ cup sour cream, 3 tablespoons unsalted butter
Spread half of the creamy pasta in the bottom of the prepared baking dish. Top with half of the meat mixture. Repeat the layers with the remaining ingredients and top with the shredded cheeses.
½ cup freshly shredded cheddar cheese, ½ cup freshly shredded mozzarella cheese
Bake, uncovered, for 25-30 minutes, or until heated through. Broil the cheese for 1-2 minutes if desired. Garnish with fresh parsley and let rest for 10 minutes before serving.
Fresh parsley