Peel onion and washed and pet dry on a cloth. Absorb extra water.

Then cut layer of the onion. Take a mixing bowl add raai and lemon juice add onion and mix well and rest 5-6 hour aside.

Take a jar clean with dry cloth.Add raai and onion add red chilli,turmeric powder, black salt, dry amchur powder, lemon juice, salt, kalonji. Mix well.

Pour into a jar and add mustard oil to it and cover it with a lid. Keep sunlight daily 8 to 10 days. Keep stir once a time daily.
Sometime stir and keep sunlight. Pickle life increases.

After 10 days your pickle is ready to eat. Serve with poori and paratha.