Twice-baked potato wedges with home-made ketchup

Serves 4

4 baking potatoes 2 tbsp olive oil, plus extra for greasing 1 onion, peeled and finely chopped 1kg tinned tomatoes 100ml red wine vinegar 100g dark brown sugar 1 cinnamon stick sea salt and black pepper 2 x 300ml bottles with lids To make the ketchup, heat 1 tbsp oil in a 2 litre saucepan. Add the onion and sauté, stirring occasionally, for 10 mins until soft. In a food processor, blend the tomatoes, then pour into the pan and mix into the onion and add the vinegar, sugar and cinnamon. Combine thoroughly, season, and bring to the boil. Simmer for 1 hr until thick and glossy. Allow to cool slightly and remove the cinnamon stick. Sterilise the two 300ml bottles, by washing them with hot soapy water, then filling a quarter of the way up with boiling water. Leave to stand for 5 mins, then pour out the water. Sterilise the lids in a small bowl, covering them in boiling water completely. Fill the bottles with the tomato sauce and seal with the lids. The sauce will keep in the fridge for 3 months. Preheat the oven to 200°C/gas mark 6 and grease a large oven tray. Pierce each potato with a fork and grease each in oil. Place on the prepared oven tray and bake for 1 hr. Allow the potatoes to cool slightly, then cut each into six lengthways and place back on the tray. Cover with the remaining 1 tbsp oil, then sprinkle liberally with salt and pepper. Bake for 30 mins until golden, then serve with the tomato sauce.