Fill a large pot with water and bring it to a boil. Add salt and spaghetti. Cook until tender according to package directions. Drain well and set aside.

Preheat your oven to 375°F (190°C). Lightly grease a 9×13 inch baking dish. This helps prevent the spaghetti from sticking during baking.

Heat olive oil in a large skillet over medium heat. Add ground beef and cook until browned. Break it into small pieces with a spoon.

Add chopped onion and minced garlic to the skillet. Cook for about three minutes. Stir often until the onion becomes soft and fragrant.

Pour marinara sauce into the skillet with the beef mixture. Add Italian seasoning, salt, and black pepper. Stir well and simmer for five minutes.

Place the cooked spaghetti into a large bowl. Add half of the meat sauce. Toss gently until the pasta is evenly coated.

Spread the spaghetti mixture in the prepared baking dish. Add small spoonfuls of ricotta cheese over the pasta. This creates a creamy layer inside the dish.

Pour the remaining meat sauce evenly over the spaghetti. Spread it gently with a spoon so the sauce covers the pasta completely.

Sprinkle mozzarella cheese and Parmesan cheese evenly on top. The cheese will melt and create a golden, bubbly layer while baking.

Place the baking dish in the oven. Bake for about 25–30 minutes until the cheese melts and becomes slightly golden.