Indian green mango pickle (Aam ka achar)

1. Wash the green mangoes and dry them thoroughly: water is the enemy of pickle, so make sure every utensil is completely dry. Cut them, skin on and including the stone area, into pieces of about 2 cm, discarding the hard stone.

2. Toss the mango pieces in a bowl with the salt and turmeric, cover and set aside for a day. The next day pour off the liquid that has come out and dry the pieces on a clean tea towel for 3-4 hours.

3. Dry-roast the mustard, fenugreek and fennel seeds in a frying pan for 1-2 minutes until fragrant, then let them cool and crush coarsely in a mortar.

4. Heat the mustard oil in a pan until it smokes (this tames its sharpness), then take it off the heat and let it cool to lukewarm. Stir in the nigella, asafoetida, chilli powder and crushed spices.

5. Toss the mango pieces thoroughly with the spiced oil and pack into a clean, dry jar so that the oil covers them.

6. Seal and leave to mature on a sunny windowsill for 7-10 days, shaking once a day. After that it keeps for months in the fridge; just a little is served at each meal, with rice, dal and paratha.

Tip: Almost every family in India has its own achar recipe, put up each summer in green mango season. If you can't get mustard oil, you can use a neutral oil, but the characteristic pungent tang will be milder.