1. Heat the olive oil in a large, lidded sauté pan and flash cook the duck fillets until just cooked, about 3 or 4 minutes on each side. Whilst the duck is cooking put the carrots, celery, onion and leek into the goblet of a food processor, chopping to quite fine dice (alternatively, roughly chop by hand).
2. Remove the cooked duck, adding the chopped vegetables and a dribble of olive oil to the pan and gently cook until beginning to soften. Whilst the vegetables cook, roughly chop the duck in the food processor.
3. Add the can of tomatoes, fish sauce, rice vinegar, red wine and seasoning to the pan – raising the temperature to bring the mixture to a fast simmer. Add the duck meat, cover and reduce the temperature to a gentle simmer and cook for about an hour, stirring from time to time and adding a little water when necessary until the sauce is richly thick and the duck meat is perfectly tender.
Check the seasoning then serve with your favourite pasta and a sprinkle of freshly grated Parmesan cheese