Step 1: Prepare the Meat Sauce

1. Cook the Beef: In a large skillet, cook the ground beef over medium heat until browned. Drain excess fat.
2. Sauté Vegetables: Add diced onion and minced garlic to the skillet. Sauté until the onion is translucent.
3. Add Marinara Sauce: Stir in the marinara sauce and dried oregano. Season with salt and pepper. Simmer for 10 minutes.

Step 2: Prepare the Alfredo Sauce

1. Heat Cream and Butter: In a saucepan, combine heavy cream and butter. Cook over medium heat until the butter is melted.
2. Add Parmesan: Stir in grated Parmesan cheese and garlic powder. Season with salt and pepper. Cook until the sauce thickens, about 5 minutes.

Step 3: Prepare the Pesto Sauce

1. Blend Ingredients: In a food processor, combine fresh basil leaves, pine nuts, grated Parmesan cheese, and garlic cloves.
2. Add Olive Oil: While the processor is running, slowly add olive oil until the mixture is smooth. Season with salt and pepper.

Step 4: Cook the Spaghetti

1. Boil Noodles: Cook spaghetti noodles according to package instructions. Drain and set aside.

Step 5: Assemble the Dish

1. Layer the Sauces and Noodles: In a large baking dish, spread a layer of meat sauce, followed by a layer of cooked spaghetti, Alfredo sauce, and pesto sauce. Repeat layers until all ingredients are used.
2. Top with Cheese: Sprinkle shredded mozzarella cheese and grated Parmesan cheese over the top.

Step 6: Bake the Spaghetti

1. Preheat Oven: Preheat the oven to 350°F (175°C).
2. Bake: Cover the baking dish with aluminum foil and bake for 20 minutes. Remove foil and bake for an additional 10 minutes, until the cheese is melted and bubbly.