How to Make It
Heat 2 very large, deep skillets. Add 2 tablespoons of the oil to each. Season the chicken pieces with salt and add half of them to each skillet. Cook over high heat until golden brown, about 3 minutes per side. Transfer the chicken pieces to a large bowl. Add the remaining 2 tablespoons of oil to the skillets along with the jalapeños and dried red chiles. Cook over moderately high heat until sizzling, about 30 seconds. Divide the onions, garlic and ginger between the skillets and cook, stirring occasionally, until deep brown, about 8 minutes.
Spoon the onion mixture into a food processor. Add the coriander, cumin, fenugreek seeds, cinnamon, cloves, nutmeg, paprika and 1 teaspoon of salt and puree. Transfer half of the onion mixture to each of the skillets. Add the tomatoes and chopped cilantro to the food processor and puree.
Return the chicken pieces to the skillets along with any accumulated juices. Cook over moderate heat, stirring, until the onion sauce begins to stick to the skillets, about 8 minutes. Stir half of the yogurt into each skillet, then stir in the pureed tomato and cilantro. Simmer the curry over moderately low heat, turning the chicken pieces occasionally, until cooked through, about 50 minutes; add 1/4 cup of water to each skillet towards the end of cooking if the sauce gets too thick. Season the curry with salt and transfer the chicken to a platter. Pour the sauce on top, sprinkle with garam masala and the cilantro leaves and serve.