Peel and finely chop the onion. Heat the oil in a pot. Brown the onion in it. Add tomatoes and bring to the boil. Add ketchup.
Season to taste with salt, pepper and sugar. Let tomato sauce cool down. Wash the maties, dab dry and cut into pieces. Add the maties to the sauce and leave to stand for 1 day
waiting time approx. 24 1/2 hours