Grind cumin seeds, black pepper, cardamom seeds, cinnamon, black mustard seeds and fenugreek seeds together well in a spice grinder or mortar and pestle.
In a small bowl, combine these ground spices, vinegar, salt, cayenne pepper and brown sugar. Set aside.
Heat half the oil in large frying pan over medium heat. Fry onions, stirring frequently, until they are a rich, dark brown. (Do not undercook the onions, this is important for colour reasons.)
Remove onions with a slotted spoon and puree them in a food processor or blender.
Return onions to pan but turn off the heat. Add 3 tablespoons water (or more if necessary) to the onions and blend until you have a smooth paste. Add the spices and mix in well. This mixture is the vindaloo paste.
Now, put the ginger and garlic in a blender. Add 1 tablespoon water (or more) and blend until you have a smooth paste.
Heat the remaining oil in a wide saucepan over medium heat. When hot, add the ginger-garlic paste. Stir until the paste browns slightly. Add the coriander and turmeric. Stir for a few seconds.
Add the chicken, a little at a time, and brown lightly.
Stir in the vindaloo paste and tomato passata. Stir and bring to a gentle boil.
Cover the saucepan, reduce heat to low, and simmer for about 45 minutes to an hour, or until chicken is cooked.
Thankyou for sharing this recipe .Just a few things to suggest .dry frying the spices brings the flavor out more and maybe using boned chicken thigh fillets as it is more juicy as has some fat content,it is also better used in slow cooked dishes.the flavors were great lou - 01 Jun 2011
Used different ingredients.
i used goat meat instead of chicken, simply because it was on special and i know has a great rich flavour.
using goat i left it to simmer for over two hours to make sure it was tender. - 14 Sep 2010