For the onion and caraway seed chutney, put the onions and sugar in saucepan with the caraway seeds. Cover with a tight-fitting lid and cook for 10 minutes over a medium heat
Add the vinegar and red wine and simmer for about 20 minutes more. Add a little blackcurrant cordial, to taste, and set aside to cool.
Meanwhile, to clean the jam jars, preheat the oven to 140C/275F/Gas 1. Wash two jars well in warm soapy water then rinse thoroughly under running water. Leave the jars and lids to dry, upside down, in the oven. (Or you can clean the jars by putting them through the hot cycle of a dishwasher.)
Carefully spoon the chutney into the sterilised jars and seal while hot. Store in a cool, dark place for up to a month if not eating immediately.
Preheat the oven to 200C/400F/Gas 6.
For the biscuits, mix the rye, wholemeal and plain flour in a large bowl. Add the seeds, chopped chives, mustard powder, salt and baking powder. Stir in the sun-dried tomato paste and olive oil until combined. Add 180ml/6fl oz water and bring the mixture together to form a dough.
Lightly flour a work surface and knead the dough for about five minutes, or until the dough is smooth and elastic (it’s ready when the dough doesn’t tear readily).
Lightly grease a large clean bowl, add the dough and cover with cling film. Set aside for 15 minutes to rest.
Meanwhile, cut out a piece of baking parchment to match the size of the baking sheet.
When the dough is rested, cut the dough in half. On a lightly floured work surface, roll out the dough using a rolling pin until it is as thin as possible. Try to keep the dough in a rectangle that will fit neatly on the baking sheet and keep lifting the dough gently to ensure it’s not sticking to the work surface (add extra flour if necessary).
Lay the prepared baking parchment on top of the dough ensuring the baking parchment covers the dough completely. Using a rolling pin to help you lift the delicate dough onto the baking sheet, roll the baking parchment and dough over the rolling pin with the baking parchment against the rolling pin. Place carefully on the baking sheet - the baking parchment should be on top.
Bake for about seven minutes, then remove from the oven and lift off the baking parchment. Flip over the dough (if you do it quickly with your hands, you shouldn’t burn yourself but you can use a tea towel to protect yourself from the hot dough) and re-cover with the baking parchment. Bake for another seven minutes.
Remove the dough from the baking parchment and sheet. Place on a work surface and, using a sharp 7cm/2¾in cutter (preferably with a handle), cut out as many circles as you can get from the dough. You may need a knife to cut through seeds.
Place each circle back on the baking sheet and return to the oven for five minutes. When crisp, place the biscuits on a cooling rack.
Repeat to use the remaining dough.
Serve the cooled biscuits with mature cheddar and a dollop of chutney.