Coarsely grate the courgettes and cucumber into a large bowl, sprinkle with sea salt, then tip into a sieve, set it over the bowl and leave to steep for a good 10 to 15 minutes.
Meanwhile, break up the bread into a medium bowl, add the milk and leave to soak.
Squeeze out any excess liquid from the salted courgette and cucumber mix, then tip them into a blender.
Add the soaked bread and any milk it hasn’t soaked up, then add the almonds, garlic, vinegar and 500ml cold water.
Blitz smooth, then taste to check the seasoning – you shouldn’t need any extra salt, but a touch of ground black pepper may be in order.
Add the basil leaves and blitz again.
Pour the soup into a large jug or bowl, then cover and chill in the fridge for at least an hour.
Once chilled, check the consistency of the soup – if you feel it’s a bit too thick, add up to 200ml more cold water, to loosen.
Ladle into bowls, top with a good drizzle of extra-virgin olive oil and a grind or two of black pepper, finish with a scattering of extra basil leaves and serve.
