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. Heat oil in a pan, and add mustard, and hing and let it cool. When the above oil becomes room temperature, mix it with the lemon, and add the roased methi powder.