Dr Michael Mosley’s purple pickled onions

This is a favourite with me and my wife. Juicy, sweet and salty pink onion rings bring crunch and flavour to almost any savoury meal. Technically, they are fermented rather than pickled in vinegar, which means they taste better, as well as enhancing your microbiome.

purple pickled onions
Image: Alex Smith. Styling: Phil Mundy

¼ small beetroot, peeled
2 large organic red onions, peeled and thinly sliced into rings
3 tsp flaked sea salt, such as Maldon
500ml jar with a well-fitting lid, cleaned
pinch of coriander seeds
½ tsp peppercorns

1. Grate the beetroot on to a board (you may need gloves to avoid staining), then put in a bowl. Add the onions and salt in a few layers.

2. Using your hands, massage the salt into the onions and beetroot. Leave for 30 minutes to two hours for the juices to appear.

3. Stuff the onion mixture firmly into the jar, sprinkling coriander seeds and peppercorns between the layers as you go, until it’s full, adding any remaining juices. Using a blunt object, such as the end of a rolling pin or the back of a spoon, press down on the vegetables to release air bubbles and submerge them in the juices. If not enough fluid is produced to cover the veg, add 1 tablespoon at a time of filtered (non-chlorinated) water to top it up until it reaches 1.5cm-2cm below the top of the jar.

4. Close the lid firmly and keep the onions at room temperature for 5-10 days. Release the gases 1-2 times a day, particularly in the first few days, pressing down to release more bubbles. (This is called ‘burping’’.) Refrigerate to slow the fermentation and they should last for 2-3 months. It should have a slightly sweet yeasty and tart smell. (Remove anything that becomes mouldy or blackened and throw it away if it smells bad.)

Buy the book with a 40 per cent discount

Fast Asleep: How to Get a Really Good Night’s Rest by Michael Mosley is published by Short Books, price £9.99. To order a copy for £5.99 with free p&p until 30 April, go to mailshop.co.uk or call 01603 648155.