Roast the fennel and coriander seeds in a pan without fat, grind in a mortar. Wash the tomatoes, grate dry, remove the stalk. Cut the tomatoes roughly. Peel onions and garlic and chop finely. Wash chillies, grate dry, remove seeds and cut into small cubes
Put tomatoes, onions, garlic, chilli cubes and lemon peel in a pot. Add spices, vinegar and sugar and bring to the boil. Simmer for about 1 hour until the mixture has a jam-like consistency. Pour into sterilized preserving jars and close them