Heat the oil in a pan. Add the rosemary, cover and leave to infuse for a moment.
Heat 1 tbsp of the rosemary oil in a pan. Sauté the shallot and garlic for approx. 2 mins. Add the parsnips and cook for approx. 2 mins. Add the Vermouth and reduce almost completely. Pour in the water, bring to the boil, season with salt. Cover and cook for approx. 20 mins. until soft. Blend the soup until smooth, stir in the sour single cream, heat through. Drizzle the soup with a little rosemary oil, sprinkle with the seeds.