Step 1

Put the limes in a saucepan and cover with water. Place a small heatproof plate on top of the fruit to keep them submerged and then bring to a boil over a medium heat and simmer for 20-30 mins until the limes are tender. Scoop out the limes, pat them dry with kitchen paper, and discard the cooking water.

Step 2

Once the limes are cool enough to handle, chop them (peel and pith included) into 3cm chunks and tip everything, including any juice, into a mixing bowl. Stir in the chopped garlic, chilli powder, turmeric and salt, and leave to one side for 1 hour.

Step 3

Heat a sturdy and dry frying pan over a medium-low heat, and add the mustard seeds, fenugreek, cumin and star anise, Stir and toast the spices for about 40 seconds until aromatic. Tip them into a mortar, add 1 teaspoon of sugar and pound to a powder with a pestle – you can also use an electric spice grinder for this, too.

Step 4

Add this ground spice mix to the limes, stir well, spoon everything into a sterilised jar and then seal. Leave the pickle in a warm place or on a sunny window ledge for 2-3 days so that flavours mature. Stir the limes once a day with a metal spoon to ensure they are evenly coated in the spice mix.

Step 5

Heat the oil in a wok or karahi over a medium-high heat and fry the ginger and green chillies for 2-3 mins, until the ginger starts to turn golden. Add the vinegar and sugar and simmer over a medium-low heat until the sugar has dissolved, then boil for 2 mins.

Step 6

Turn the heat off and add the steeped limes and masala. Leave on one side to cool and then spoon the pickle back into the same jar. Using a metal spoon, push the limes down into the jar so that they are covered by the spicy oil – you might need to add a little extra oil. Seal the jar and leave the pickle for 3-4 days before tasting. It will keep for 3 months at room temperature.