Up your fermentation game with these garam masala cherry tomatoes

Keep a jar of these in your fridge for pasta, toast toppings or side dishes. By Prudence Wade

Are you brave enough to leave them to fizz for a fortnight? (Mark Diacono/PA)

This is quite the experience: the tomatoes turn beautifully fizzy on the tongue, crazily so if you leave them to ferment for a fortnight,” says food writer Mark Diacono.

“You can spice them how you like: here, all the spices from a classic garam marsala quietly infuse the brine and then the tomatoes. The result is gentle but clear, each spice singing its note in a choir of soft sourness.”

Garam masala cherry tomatoes

Makes: 700ml jar

Ferment time: Up to two weeks, or longer for the brave

Ingredients:

1 tbsp cumin seeds

1 tbsp ground coriander seeds

1 tbsp fennel seeds

6 cardamom pods, seeds only

2 cloves

625g cherry tomatoes, washed and stems removed

400ml 5% brine

Method:

1. Lightly bash the spices to encourage them to release their scent and flavour.

2. Fill the jar with the tomatoes and add the spices.

3. Pour the brine to within no nearer than two centimetres of the rim. To make the 5% brine, use five grams salt for every 100ml water. It is easiest to dissolve salt in hot water, yet ideally the brine should be cool when poured over the ingredients. It helps to dissolve the salt in a quarter to a third of the water as boiling water, stirring vigorously, before adding the rest as cold water.

4. Secure the lid and leave to ferment out of direct sunlight in a warmish place, lifting the top at least once a day to release any pressure, and inverting to encourage the spices to mix.

5. After five days, taste a tomato: it should be salty, sharp, spicy, slightly fizzy and delicious. Give it a few more days if you want the flavour to develop.

Recipe from ‘Ferment’ by Mark Diacono (published by Quadrille, £12.99; photography by Mark Diacono), available March