Heat the mustard and coriander seeds in a dry frying pan, stirring over a medium heat until they start to pop. Remove from the pan and lightly crush in a pestle and mortar or with a rolling pin. Set aside.

Place prepared tomatoes, onions, chillies, garlic, ginger, sugar, vinegar, 1 tb smoked paprika, the crushed mustard and coriander seeds, 1 tsp salt and some chilli flakes (optional) into a large, stainless steel or enamel lined saucepan.

Put a lid on the pan while bringing to the boil, then remove the lid, turn down the heat and simmer gently until the vegetables are soft (approx 1 hour).

Take the saucepan off the heat and, using a handheld stick blender, reduce the mixture to a chunky puree.

Taste, and add more chilli flakes or smoked paprika if desired.

Put washed, rinsed and drained jars and lids on a baking tray and place into a low oven. Turn off the oven when the jars are hot, but leave them inside until you're ready to pot the finished chutney.

Bring back to a boil and continue to gently cook, uncovered and stirring regularly (careful: it may splutter!), until there’s no loose liquid when a wooden spoon is drawn across the bottom of the pot (approx. 1 hour).

Taste seasoning again, adding more salt, chilli flakes or smoked paprika if needed.

Put into clean, warm jars, lightly screw on the lids and leave to cool.

When cool enough to handle, tighten the lids a little more if possible.

When completely cold, test that you have an airtight seal by pressing the centre of the lids:

- if it is already down or stays down then you do have an airtight seal

- if the centre of the lid pops up again, see Recipe Notes below for what to do.

Label and leave to mature for 6 weeks. Should keep for a year in a dark, cool place.