Fresh tomatoes: cut a small cross on the top of each tomato, place in large bowl, cover with boiling water, leave for a minute. Drain and rinse with cold water, peel off skins.
Tinned tomatoes: drain off juice and set aside.
Roughly chop the tomatoes; finely chop the onions and garlic.
Place the tomatoes, onions, garlic, sugar, vinegar and salt in a large saucepan and bring to the boil, reduce to a medium heat and gently cook for 15-20 mins.
Mix the curry powder, mustard and cornflour with the extra vinegar to a smooth paste, stir into the tomatoes and cook until thickened.
Spoon into warm, sterilised jars and seal. Refrigerate once opened.
Makes: 1 large 500ml jar.