Place ground meat in a large bowl. Add breadcrumbs, egg, garlic, milk, salt, pepper, and oregano. Mix everything gently using hands or a spoon. Make sure ingredients are well combined but do not overmix.

Take small portions of the mixture. Roll them into even-sized balls using your hands. Place them on a tray. Keep them slightly firm but not too tight.

Heat a pan with a little oil. Place meatballs carefully and cook until they turn golden brown. Turn them slowly so all sides cook evenly. Remove and set aside.

In a saucepan, heat olive oil over medium heat. Add chopped onions and garlic. Cook until soft and fragrant. Stir often to avoid burning. If you love building deep, meaty tomato sauces, you might also enjoy making a slow-cooked beef and tomato pasta sauce that develops incredible depth of flavor.

Pour crushed tomatoes into the pan. Add salt, pepper, and sugar. Stir well and let the sauce simmer for 10 to 15 minutes until it becomes thick and rich.

Add cooked meatballs into the tomato sauce. Stir gently so they are covered well. Let them cook together on low heat for 15 minutes.

Let everything simmer slowly. This helps meatballs absorb the sauce flavor. The sauce should become thick and glossy.

Turn off heat and garnish with fresh basil leaves. Serve warm with pasta, rice, or bread.