Peel and finely chop the onion. Peel, wash and cut the potatoes into small pieces. Melt butter in a pot. Sauté potatoes and onions in it. Add stock and vinegar.
Bring to the boil, cover and cook for about 20 minutes. Meanwhile roast sunflower seeds in a pan without fat until golden brown, take them out. Peel and wash the carrots and cut or slice them into fine strips.
Heat 1 tablespoon of pumpkin seed oil and 2-3 tablespoons of water in a coated pan. Steam carrot strips in it for 3-4 minutes until al dente, season with salt and pepper. Puree the soup finely. Stir in cream, season with salt, pepper and sugar.
Add the carrot strips to the soup and warm them up. Arrange the soup and sprinkle with sunflower seeds and sprinkle each with about 1/2 tablespoon of pumpkin seed oil.