Peel the cucumbers, cut off the ends, cut in half lengthways, scrape out the seeds with a spoon and cut the pulp into pieces.

Peel off the sushi ginger and puree with the cucumber pieces in a tall, narrow container with a hand blender. Mix in the thick milk with the lemon juice, salt and pepper and cover in the freezer for about 3 hours. Stir in between. Season to taste before serving, carefully lather the surface with the hand blender. Place the crab topping and garnish with dill, balsamic vinegar and chilli flakes.