Chop the onion. Peel and chop the celery and potatoes. Cut the chilli pepper in half and scratch the seeds out with the back of the knife. Chop finely.
Heat the cumin in a large pot until it starts to steam a little. Add the butter. Lightly braise the onions, celery and chilli for 5 minutes without colouring. Add the potatoes and deglaze with the white wine. Allow the liquid to reduce.
Once the white wine has been reduced, pour in the vegetable stock and season with salt and pepper. Cook covered for about 20 minutes until the vegetables are soft.
Add the cream and blend the soup finely. Season to taste again and divide among four NewMoon soup plates. Refine and garnish the soup with the reduced balsamic vinegar. Then sprinkle with the shiso cress and serve.