Step 1

• Prepare the Marinade: In your blender or food processor, combine the rough chopped onion, along with the garlic, ginger, and red chilies. Pulse until finely chopped. Add the spices along with the vinegar; process until it is a fairly smooth paste, stopping to scrape down the sides as necessary. Place the chicken pieces in a zip-top bag and add the marinade, smooching it around so that all the chicken is coated. Remove as much air as possible from the bag and marinate in the refrigerator for at least an hour, better for more. (I did 4 hours).
• When ready to cook, in a sauté pan, heat the oil and ghee together over medium heat, when hot add the diced onions, along with a pinch of salt, and cook, stirring frequently until they just begin to brown around the edges, about 5 - 7 minutes. Add the chicken, along with the marinade and cook for 5 minutes, stirring it around, then add the chicken stock and tomatoes, stir and bring to a simmer. Cover the pan and lower the heat slightly, cook for ½ hour (if using thighs; if using breast, add the potato now so the breast doesn't get overcooked). Uncover the pan and add the potatoes; simmer, uncovered for about 20 minutes, or until the potato is tender, stirring occasionally. Taste and adjust for salt, pepper, and heat (add a little more cayenne if you desire hotter). Garnish with cilantro, if using and serve with some steamed basmati rice (or other rice of your choice).