In a large pot, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent.

Add the minced garlic and cook for another minute until fragrant.

Stir in the crushed tomatoes, tomato paste, and sugar. Mix well.

Add the dried oregano, basil, salt, and black pepper. Stir to combine.

Bring the sauce to a simmer, then reduce the heat to low and cover. Let it cook for at least 2 hours, stirring occasionally.

If using sausage and meatballs, add them to the sauce during the last hour of cooking.

Taste and adjust seasoning if necessary before serving.