Photograph: Karen Thomas
In a large pan, cook the onion and celery in the olive oil over a lowish heat for 15 minutes, or until softened.
Add the chopped tomatoes, sugar and the hot stock and bring to the boil. Reduce the heat and simmer, covered, for 10 minutes.
Meanwhile, in a small pan, separately toast the sesame seeds, coriander seeds and nuts. The sesame seeds and nuts are ready when they're golden; the coriander seeds will take about 30 seconds – until they smell fragrant. Leave to cool for a few minutes, then crush the coriander seeds using a pestle and mortar and mix with the sesame seeds. Finely chop the toasted hazelnuts.
Tip the goats' cheese into a bowl and whisk it for a few minutes with an electric whisk, then fold in the toasted seeds and half the hazelnuts.
Whiz the tomato soup in a food processor or blender until smooth, then return it to the pan, season to taste and warm it through. Or, if you are serving the soup cold, cool it before chilling thoroughly.
Serve in glasses or bowls with a spoonful of whipped dukkah goats' cheese added to each. Finish with a sprinkling of the reserved hazelnuts.
You can make the soup up to 3 days ahead. It freezes well, too.