Peel and clean the pumpkin and cut into cubes. Peel and slice the carrots. Peel, wash and chop the potatoes. Heat butter in a pot. Fry the vegetables lightly for 3-4 minutes while turning.
Halve the orange and squeeze the juice. Pour vegetable stock into the pot, bring to the boil, season with cumin, pepper and carefully with salt. Cover and simmer for about 30 minutes.
Roast caraway seeds in a pan without fat for 2-3 minutes while turning. Leave to cool on a flat plate. Finely puree the soup with the cutting stick. Season to taste with salt, cumin and pepper.
Wash the chervil, shake dry and pluck off the leaves. Arrange the soup and garnish with crème fraîche, caraway seeds and chervil.