Mexican pickled red onions

These crisp, pink onions are a traditional Yucatan accompaniment for cochinita pibil, and oh, my beating heart, they're good. Red onions are par-boiled very briefly, then semi-preserved in a citrus, sugar and salt mixture spiked with chillies and cumin. They'll keep in the fridge for up to a month, which is good, good news, because besides being a perfectly pitched addition to a taco, these are one of the best accompaniments for strong cheeses I've come across. (Try some alongside a Stilton or some Gorgonzola.) They're great to look at, too; the acid in the preserving mixture turns the red onion, which acts as a universal indicator, a really vibrant pink.

I've used a little home-made habanero vinegar in the preserving mixture. It's a particularly delicious vinegar (and very easy - just steep a few whole habaneros in a bottle of white wine vinegar for a couple of weeks) - it picks up all the citrusy, fruity undertones of the habaneros and packs plenty of heat.

To make a large bowl of Barbie-toned pickled onions, you'll need:

2 medium red onions
Juice of 1 orange
Juice of 3 limes
Juice of 2 lemons
2 tablespoons habanero vinegar (white wine vinegar in which you've steeped a few habanero chillies for a week or so - see above)
1 teaspoon cumin
1 tablespoon sea salt
1½ tablespoons caster sugar

Halve the onions, and cut into slices. Bring a saucepan of water to the boil and drop in the onion slices. Count to twenty and drain the onions, and set aside in a large bowl.

Stir the citrus juices, vinegar, cumin, salt and sugar together in a saucepan and bring to the boil, stirring until the sugar and salt has dissolved. As soon as the mixture starts boiling, remove it from the heat and pour it over the onions. Cover the bowl and refrigerate until cold (a couple of hours).