1️⃣ Preheat the Oven:

• Preheat your oven to 375°F (190°C).
• Lightly grease a 9×13-inch baking dish and set it aside.

2️⃣ Cook the Pasta:

• Bring a large pot of salted water to a boil.
• Cook the pasta shells until al dente, according to package instructions.
• Drain and set aside.

3️⃣ Prepare the Beef Mixture:

• Heat olive oil in a large skillet over medium heat.
• Add the chopped onion and minced garlic, cooking until softened and fragrant.
• Add the ground beef and cook until browned, breaking it into small crumbles.
• Drain any excess grease, then stir in the tomato sauce, Italian seasoning, salt, and pepper.
• Let the mixture simmer for 5 minutes.

4️⃣ Make the Creamy Sauce:

• In a mixing bowl, combine sour cream and cream cheese until smooth.
• Stir this creamy mixture into the beef and tomato sauce in the skillet, mixing until fully incorporated.

5️⃣ Assemble the Casserole:

• Layer half of the cooked pasta shells in the prepared baking dish.
• Pour half of the beef and cream mixture over the pasta.
• Repeat with the remaining pasta and sauce.
• Top with shredded cheddar and mozzarella cheeses.

6️⃣ Bake the Casserole:

• Cover the casserole dish with aluminum foil.
• Bake for 20 minutes.
• Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.

7️⃣ Garnish and Serve:

• Let the casserole rest for 5 minutes after removing it from the oven.
• Garnish with fresh parsley and serve hot.