Spice Traders' Chicken Curry - cooking recipe

Ingredients

1 1/4 cups onions, finely chopped
2 garlic cloves, chopped
1 piece ginger, chopped (half-inch)
1 hot green chili pepper (optional)
2 tablespoons vegetable oil
1/2 teaspoon cumin seed
1 cup tomatoes, diced (canned or fresh)
2 tablespoons sour cream
2 tablespoons yogurt, plain (not low-fat)
1 teaspoon ground coriander
1/2 teaspoon ground cumin
1/2 teaspoon turmeric
1/4 teaspoon cayenne pepper
1/4 teaspoon ground black pepper
1/2 teaspoon garam masala
1 teaspoon kasuri methi (dried fenugreek leaves)
salt (to taste)
2 lbs chicken thighs, skinned, bone-in, washed, and drained (or 8 boneless thighs)
1 tablespoon lemon juice
2 tablespoons fresh coriander leaves, chopped

Preparation

Mince the onions, garlic, ginger, and chili in a food processor.
Warm the oil in a nonstick skillet over medium-high heat. Add the cumin seeds. After a few seconds, when they begin to sputter, add the minced onion mixture.
Saute, stirring occasionally for 5 to 10 minutes, until the onions are browned.
Process the tomatoes in the food processor until smooth.
Reduce the heat to medium under the skillet and add the tomatoes. Cook for 5 to 8 minutes, until all the liquid has evaporated and the oil appears around the edges.
Add the sour cream and the yogurt and stir continuously for about 5 minutes, until the oil appears again.
Add all the spices and salt and cook for one minute.
Now add the chicken thighs, coating well with sauce. Cover and bring to a boil.
Immediately reduce the heat to medium-low and cook, stirring occasionally, for 30 minutes, or until the chicken is tender.
Uncover and mix in the lemon juice and fresh coriander leaves.
Transfer to a serving dish and serve alongside plain rice.