Via: Toby Scott
Heat the salt in 500ml boiling water until dissolved. Dilute it with 1 litre of cold water, then pour this into a very large glass or china bowl and set aside to cool.
Separate the cauliflower into small florets, discarding any thick stems. Quarter the shallots and cut the courgettes, beans and pepper into 2cm pieces. Put the vegetables in the cold brine, cover and leave for 12-18 hours.
The next day, preheat the oven to 120°C/gas mark 2. Drain the vegetables and wash them thoroughly under a cold running tap. Put some tea towels or kitchen paper on the counter and let the vegetables drain in a single layer for about 20 minutes. Put 6 x 350g jam jars and their lids in the oven to sterilise them while finishing the recipe.
In a small food processor, whizz the garlic, peeled ginger and chillies together to make a paste. If you want a milder sauce, remove the seeds from the chillies before you process them.
Grate the peeled apple, discarding the core. Put the apple and the spice paste into a large heavy-bottomed pan and mix in 250ml vinegar. Place the pan on the heat, bring to a simmer, then cover and cook for 5 minutes.
Mix the sugar, mustard powder, turmeric and cornflour together in a bowl and, using another 250ml of the vinegar, gradually mix to a smooth liquid. Add the remaining 250ml vinegar, then scrape this into the pan.
Over a low heat, bring the sauce to a simmer, stirring constantly, then cook for 3-4 minutes or until you can no longer taste raw cornflour. The sauce should be very thick at this stage.
Put the vegetables into the pan and stir well. The sauce may not completely cover them, but stir them around. Cook over a gentle heat, stirring often, for 10 minutes until the vegetables just soften. The sauce may thin a little as some of the juice from the vegetables comes out.
Spoon the piccalilli into the hot jars, packing it down well and making sure the vegetables are covered by the sauce. If you're low on sauce, pour over a little extra vinegar and seal.
Allow them to cool, then label and store in a cold, dark place for 6-9 months.