Peel and finely chop the shallot. Heat the olive oil in a large pan and sauté the shallots for 5 minutes, then sprinkle with curry powder and sugar and roast briefly.
Add the tomato purée and apple cider vinegar. Simmer everything with the lid open over a low heat for approx. 30 minutes until the consistency resembles ketchup.
Season the curry ketchup with all the ingredients used as well as salt, pepper and chilli powder if necessary, puree to the desired consistency, then leave to cool and store in the fridge until ready to eat.
