Finely dice the shallots, wash and chop the carrots, apple and celery.
Put everything in an unperforated steamer basket, add the chicken stock, add the butter and season with salt, lemon juice, coriander and pepper.
Steam in a steamer at 100°C for 30 minutes until soft. Add sour cream and puree finely with a hand blender. Season a little more if necessary.
Before serving, whisk well and sprinkle with toasted sesame seeds.