Scrape the peel from the ginger with a spoon, then coarsely chop ginger. Blend the ginger and garlic into a smooth paste using a mini food processor. Alternately, finely grate the ginger, mince the garlic, and combine. (You'll have enough for this recipe plus extra for another use.) Set 1 1/2 teaspoon, and 1 tablespoon of ginger-garlic paste aside and refrigerate leftovers, covered, for up to one week.

Cut the chicken into 2-inch pieces. In a large bowl, combine chicken with the 1 1/2 teaspoon of reserved ginger-garlic paste, the yogurt, coriander, salt, turmeric, oil, and Kashmiri chili.

Heat a large cast-iron skillet over high heat. Add the chicken mixture and cook, turning occasionally, until lightly charred (chicken may not be quite cooked through), about 5 minutes. Transfer to a large bowl.

Reduce heat to medium-low. Add the oil and reserved 1 tablespoon of ginger-garlic paste. Cook, stirring, until slightly softened, 10-15 seconds.

Add the coriander and cumin and stir until sizzling, then stir in the tomatoes. Continue to cook over medium-low until tomatoes have softened and most of the liquid has cooked off, 5-8 minutes.

Transfer the tomato mixture to a blender and add the cream. Blend into a smooth paste. Add the water and blend again.

Return tomato mixture to the skillet, add the chicken, and stir well to combine. Cover and cook over medium-high heat until chicken is cooked through and flavors are blended, 3-5 minutes.

Remove chicken from the heat. Sprinkle the fenugreek on top, if using. Let chicken stand, covered, 5-10 minutes before serving for flavors to blend. Serve with basmati rice.