Instructions:

• Heat the oil in a large pan. Add the onions and 1 tsp salt and cook over a medium heat until light golden brown, about 8 minutes. Add the ginger, garlic and green chilli cumin seeds, green chill, ajwain, bay leaf, cloves, green cardamom (seeds only), whole black cardamom, asafoetida and turmeric. Saute for 2-3 minutes. Add the tomato puree and cook for 30-40 seconds before adding 200ml of water. Cook until reduced by half. Allow to cool.
• Blend the onion and spice mixture in a high-powered blender until smooth, about 2 minutes.
• Rinse the same pan used for the sauce and wipe with a paper towel. Heat the butter in the pan and then add the chilli powder, kasoori methi and garam masala. Sizzle for a moment and then add the blended paste. Pour the remaining 200ml water into the blender jar and shake to remove any sauce left inside — pour this into the pan, too.
• Add the beans (along with the cooking liquor) and season with salt, sugar and lemon juice. Bring to the boil and cover with a lid. Simmer over a medium heat for 10 minutes, stirring halfway to prevent the beans sticking to the bottom of the pot. Remove the lid and cook for a further 10 minutes to evaporate excess water and thicken the sauce. Serve with rice, papad (poppadoms), sliced onions, chillies, lemon wedges and butter (optional).