DUKKAH TO SERVE (OPTIONAL) - MAKES ABOUT 225 G / 8 OZ:
140graw unsalted hazelnuts
1tbspwhole black peppercorns
75graw unsalted sesame seeds
1tspfine sea salt - plus extra as needed
TO MAKE THE SOUP
In a blender, combine the cucumbers, avocados, lemon juice, mint leaves, salt, oil, chives, parsley and water, and blend on high until the mixture is as smooth as possible. Strain through a fine sieve for extra smoothness, if desired. Season with salt.
Place in the fridge to chill for at least 2 hours to allow the flavours to meld. Enjoy cold, topped with Dukkah, if liked.
FOR THE DUKKAH
Preheat the oven to 160°C / 325°F / Gas mark 3. Spread the hazelnuts out in a single layer on a rimmed baking sheet and roast for 20–30 minutes until fragrant and the skins have turned darker in colour. (Another good way to check for doneness is to bite a hazelnut in half and inspect the colour – it should be golden, not white, inside.) Remove from the oven, and when cool enough to handle, rub the nuts together to remove the skins. Place the nuts in a food processor.
While the hazelnuts are roasting, preheat a dry frying pan over a medium heat. When hot, toast the coriander and cumin seeds, stirring often, until fragrant, about 2 minutes. Remove the pan from the heat immediately, leave the seeds to cool, then place them in a mortar and pestle and add the peppercorns. Using the pestle, grind the seeds and peppercorns together until pulverized. (Alternatively, grind them together in a coffee mill or food processor.) Set aside.
In the same frying pan, toast the sesame seeds for about 2 minutes until they are fragrant and begin to pop. Leave to cool slightly. Place the sesame seeds in the food processor with the hazelnuts. Pulse to chop the mixture until you get a chunky-sand texture. (Do not blend, or you will end up with hazelnut-sesame butter! Tasty, but not what we’re after.)
Add the pulverized spices and the salt to the food processor and pulse once more to combine. Taste and adjust the seasonings, if necessary. Store in an airtight glass container at room temperature for up to 1 month.