Heat the oil with the butter in a large saucepan, lightly fry the onion in it. Add the prepared carrots, pumpkin and parsnips, stir in. Cover and fry for 5 minutes over low - medium heat. Now pour in the broth and season with salt and pepper. Bring to the boil and simmer covered for about 30 minutes. The vegetables should then be soft!
Then let the whole thing cool down, puree everything finely. If the soup is still a little too thick, add water. Reheat to serve and add lemon juice to taste.