Place the onion, fennel and celery in a large saucepan with some olive oil, the ginger, garlic, chopped chili, basil stalks, coriander seeds and garlic cloves and season with salt and the 1 tsp black pepper.

Over a low heat, cook for about 12 minutes, until the vegetables have softened, stirring occasionally.

Add 1 1/2 cups water and the tomatoes. Let simmer gently until the liquid is reduced by half.

Add the basil leaves, pour the sauce in a blender or food processor and process until very smooth. Strain the sauce through a sieve into a clean saucepan and add the vinegar.

Simmer again until it reaches the desired ketchup consistency. Adjust the seasoning to taste. Cool in the refrigerator and enjoy. This ketchup recipe can be bottled in sterilized jars and kept for up to 6 months in a cool dark place.