Ginger garlic paste:Place ginger, garlic and green chilies in a food processor. Process to a smooth paste. Set aside.
Place lamb in a bowl. Add ginger-garlic paste. season with salt. Toss to coat. Cover and marinate in refrigerator for about 30 minutes.
Lamb karahi:Heat oil in a large pan over medium-high heat. Add onions. Sauté, stirring occasionally, for 2-3 minutes or until soft and translucent. Add lamb. Sauté, stirring occasionally, for about 5 minutes or until it starts to brown.
Add ground turmeric, ground cumin, ground coriander, black pepper powder, garam masala and red chili powder. Sauté, stirring, for 1 minute or until fragrant.Stir fry for 10 minutes. Add tomatoes. Stir to combine. Simmer for 15 minutes or until tomatoes turn mushy.
Add yogurt. Pour in 1 cup water. Stir to combine. Cover and cook for about 45 minutes. Remove lid. Add kasuri methi (dried fenugreek leaves) and coriander (cilantro) leaves. Stir to combine. Heat through.
Garnish with ginger and coriander (cilantro) leaves.