Punjabi aam ka achar

Step 1: Wash the 2 ¼ lb firm raw mangoes and dry it completely. With a heavy cleaver cut each mango into 3 cm chunks, cutting through the soft young stone; discard the hard inner kernel shell if it has formed.

Step 2: Toss the pieces with 2 tbsp salt and 2 tsp ground turmeric in a dry bowl and leave for 2 hours.

Step 3: Drain, then spread the pieces on a clean cloth in the sun (or a warm, airy room) for a full day, until the surfaces are dry and the edges slightly shrivelled.

Step 4: Sterilise the jar and lid: wash in hot soapy water, rinse, then dry in a 250°F oven for 15 minutes (or in strong sun for a few hours). Cool completely; jar, lid, bowls, spoons and your hands must be bone dry.

Step 5: Dry-roast 4 tbsp fennel seeds (saunf) and 2 tbsp fenugreek seeds (methi dana) in a pan over a low heat for 2 minutes until fragrant, cool, then coarsely crush with 2 tbsp yellow mustard seeds in a mortar or with a few pulses in a grinder. Mix in 1 tbsp nigella seeds (kalonji).

Step 6: Heat 1 ¾ cups mustard oil in a pan until it smokes and turns pale, then turn off the heat and let it cool until just warm, about 15 minutes. Common mistake: skipping the smoking step, which leaves the oil harsh.

Step 7: Stir ½ tsp gluten-free asafoetida, 3 tbsp red chilli powder, 1 tsp ground turmeric and 1 ⅜ oz salt into the crushed spices, add 4 tbsp of the warm oil and mix, then add the mango and toss until every piece is coated.

Step 8: Pack into the jar and pour over the rest of the oil once it is cold, so it covers the mango by 2 cm. Tie muslin over the mouth.

Step 9: Set the jar in the sun every day for 7 days, shaking or stirring with a dry spoon daily, then close the lid. It is ready when the mango is tender with a little bite. Keep the pieces under oil, store in a cool cupboard for a year and discard if mould appears.