Moroccan Vegetable Soup

From Soup: Superb Ways With a Classic Dish by Debra Mayhew.
Ingredients:
1 Tbsp. olive or sunflower oil
1 Tbsp. butter
1 onion, chopped
8 oz. carrots, chopped
8 oz parsnips, chopped
8 oz. pumpkin or squash, chopped
About 3 3/4 c. vegetable stock
Lemon juice, to taste
Salt
Freshly ground black pepper
A good pinch of paprika

Heat the oil and butter in a large pan and fry the onion for about 3 minutes until softened, stirring occasionally. Add the carrots and parsnips, stir well, cover and cook over a gentle heat for a further 5 minutes.
Cut the pumpkin into chunks, discarding the skin and pith, and stir into the pan. Cover and cook for a further 5 minutes, then add the stock and seasoning and slowly bring to the boil. Cover and simmer for 35-40 minutes until the vegetables are tender.
Allow the soup to cool slightly, then pour in to a food processor or blender and purée until smooth, adding a little extra water if the soup seems too thick. Pour back into a clean pan and reheat gently.
To make the garnish, heat the oil in a small pan and fry the garlic and herbs for 1-2 minutes. Add the paprika and stir well.
Adjust the seasoning of the soup and stir in lemon juice to taste. Pour into bowls and sprinkle with paprika.