The evening before: peel the cucumber, cut a few slices lengthwise, very kle= in cubes and put to cool, coarsely chop the rest of the cucumber. Peel onion, potato and garlic, also chop coarsely, sauté together with cucumber in olive oil, season with salt and pepper. Add the chicken broth and cook for twenty minutes. In the meantime, cut the toast into cubes and toast in a non-stick frying pan with a tablespoon of butter until golden brown. Remove the croutons from the frying pan, season with salt and set aside. Blend the soup in a hand mixer, cool and leave to cool overnight.
In the morning, before work: make the soup bubble with crème fraîche. Grate horseradish, chop cilantro, and add both to soup. Fill soup into a thermos. Pack in diced cucumber and croutons for sprinkling and – if you like – a small bottle of olive oil to drizzle over the soup.