How to Make It
In a large, resealable plastic bag, combine the yogurt and 1/4 cup of the grated onion. Season the chicken generously with salt and pepper and add to the bag; seal and refrigerate for 1 hour.
In a small bowl, cover the cashews with the boiling water and let soak for at least 1 hour or up to 8 hours.
In a large skillet, combine the oil and remaining 1 cup grated onion and cook over moderate heat, stirring frequently, until the onion softens, 8 to 10 minutes. Add the garlic, ginger, jalapeño, garam masala and tomato paste and cook until fragrant, about 2 minutes. Add the tomatoes, sugar and salt and bring to a simmer. Reduce the heat to moderately low and simmer gently for 15 minutes. Turn off the heat and let the masala sauce cool, uncovered, for 10 minutes.
Meanwhile, preheat the broiler on high. Remove the chicken from the marinade, scraping off any excess, and arrange on a broiler pan or a wire rack fitted inside a baking sheet. Broil the chicken 4 to 6 inches from the heat for about 5 minutes, until slightly charred. Turn the chicken and broil for about 3 minutes longer, until the chicken is cooked through. Let the chicken rest for 5 minutes, then dice.
In a blender, combine the cashews and their soaking water and puree until smooth. Carefully ladle the masala sauce into the blender and puree with the cashews, in batches if necessary, until completely combined and smooth. Return sauce to the skillet and fold in the diced chicken and cilantro leaves and cook over moderate heat until hot.
Tip: Omit the cashews and use heavy cream or coconut milk for a rich finish to the sauce. Tip: Make an Indian pizza by using a frozen naan as the crust, a jarred curry sauce instead of tomato sauce, and chopped leftover chicken and mozzarella cheese as a toppings. Tip: Wrap leftover chicken in pita or laffa bread for lunch the next day. One serving: 377 cal, 12 gm fat, 3 gm sat fat, 15 gm carb, 2 gm fiber, 50 gm protein.