Preheat your oven to 350°F (177°C) and grease a 9x13-inch baking dish with nonstick spray.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the finely chopped onion and green bell pepper, sautéing for about 5 minutes until they become translucent.

Add 1 pound of ground beef to the skillet and cook until browned, around 7-10 minutes. Drain excess fat, then season with salt, black pepper, and Italian seasoning. Stir in 1 ½ jars of spaghetti sauce.

In a large pot, bring salted water to a boil and add 16 ounces of spaghetti. Cook until al dente, about 8-10 minutes. Drain and run cold water over it.

In a medium saucepan, melt ½ cup of butter over medium heat. Sauté 2 cloves of minced garlic for 30 seconds. Whisk in ½ cup of flour to create a roux, then gradually stir in 2 cups of heavy cream.

Toss the drained spaghetti with the creamy Alfredo sauce in a large mixing bowl until well coated. Layer it into the prepared baking dish.

Spoon the reserved meat sauce evenly over the spaghetti.

Sprinkle 2 cups of shredded mozzarella cheese over the meat sauce.

Bake in the preheated oven for 30 minutes until the cheese is bubbly and golden brown.

Allow to cool for about 10 minutes before serving.