Arrange all ingredients for use.
Soak the toast in a little lukewarm water.
In a bowl, mix the egg with the mince.
Squeeze out the liquid from the toast then add to the bowl.
Add the parsley. Season with salt and pepper. Knead well to combine.
Using damp hands, shape the mixture into small balls.
Heat a little oil to in a non-stick pan and add the meatballs. Cook, turning, until browned all over. Remove from the pan.
Peel and finely dice the onion. Heat some more oil in the pan and fry the onion until softened. Stir in the tomato puree.
Add the tomatoes and simmer gently for 10 minutes.
Season with salt and pepper. Stir in the olives and oregano leaves. Return the meatballs to the sauce, heat through and serve.