In a small bowl, soak bread slices in milk until soft and all the milk has been absorbed (add more milk if needed).
Then transfer to a large bowl and add grated onion, ground beef, egg, curry powder, turmeric powder, 1-teaspoon oregano, salt and pepper. Mix well to thoroughly incorporate.
Form into golf ball-size meatballs.
Heat 2-3 tablespoons oil in a large non-stick frying pan over medium-high heat. Fry the meatballs until they are browned all over (Cook in a single layer. Do not over-cook). Set aside.
Mix the grated tomatoes, crushed tomatoes, 1-teaspoon oregano, salt and pepper. Spread 3-4 tablespoons of tomato sauce over the bottom of a large pot. Place the meatballs into the pot and pour the remaining sauce over the meatballs. Cover the pot and bring to a boil. Then reduce heat to medium-low and simmer covered until cooked through and sauce is thickened, about 30-40 minutes. Do not stir meatballs with a spoon, just move the pan occasionally. Serve curried meatballs with rice, bread or pasta.