1. Blitz the mango, pineapple, chillies and salt in a food processor to form a coarse puree. Fold in the passionfruit pulp.

2. Transfer to a clean jar and cover the surface with plastic wrap. Weigh down with fermentation weights or a ziploc filled with water. The puree will rise in the jar as it ferments. Check the flavour after 7 days. If it has a pleasantly sour flavour, it's ready.

3. Transfer mash into a food processor a second time and blitz until smooth.

4. Pour the sauce into a clean bottle and store in the fridge for 3-6 months, removing the lid occasionally to allow any gas to escape. You don't want hot sauce blowing up in the fridge!

More summer recipes and hot sauces from Rosheen Kaul