Spice Traders' Chicken Curry

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