South Indian pineapple chutney

Sterilise a 500ml jar (or a few smaller ones) according to the online instructions at waitrose.com/howtosterilisejars. Heat 1 tbsp oil in a large pan over a medium-low heat and fry the onion until soft and translucent (8-10 minutes). Add the ginger and red chillies; fry for 3-4 minutes, then add the coconut and fry until toasted. Cool, then tip into a high-speed blender and whizz with 50ml water until you have a thick paste.

In the same pan, heat the remaining 1 tbsp oil, then add the mustard seeds. As soon as they pop, add the asafoetida, if using, and curry leaves. Fry briefly, then add the cumin, coriander, fenugreek and nigella seeds.

Once fragrant, add the chilli paste, sugar, vinegar and pineapple; simmer over a low heat for 30-45 minutes, stirring occasionally, until the pineapple has broken down and the sauce has thickened. Pour into the sterilised jar(s) and allow to cool before covering. Keep in the fridge for up to 1 month.