Place all the vegetables in a large heavy-bottomed saucepan with a big splash of olive oil and the ginger, garlic, chilli, basil stalks, coriander seeds and cloves. Season with a teaspoon of black pepper and a good pinch of sea salt.
Cook gently over a low heat for 10 to 15 minutes, or until softened, stirring every so often. Add all the tomatoes and 350ml of cold water. Bring to the boil and simmer gently until the sauce reduces by half.
Add the basil leaves, then whiz the sauce in a food processor or with a hand blender and push it through a sieve twice, to make it smooth and shiny. Put the sauce into a clean pan and add the vinegar and the sugar.
Place the sauce on the heat and simmer until it reduces and thickens to the consistency of tomato ketchup. At this point, correct the seasoning to taste.
Spoon the ketchup through a sterilized funnel into sterilized bottles, then seal tightly and place in a cool dark place or the fridge until needed – it should keep for six months. Great served with steak and chips.