Cut lemon into small dices, add salt, turmeric, and keep it aside for 4-5 days. Add red chilli powder to this lemon and mix it well. Roast methi seeds and dry grind it and keep it aside. Bring 2 cups of water to a boil and add this to the soaked lemon. Fry mustard, hing, green chillies, and ginger in oil and add this to the lemon. Add the roasted methi powder when the above is cool (ie) room temperature.