Peel the turnip and cut into cubes. Peel and finely chop the onion. Heat oil in a pot. Sauté the onion and turnip for about 5 minutes, turning. Add stock and milk, bring to the boil and simmer for about 20 minutes.
Puree with a blender, pass through a sieve and bring to the boil. Crumble 2 pretzels. Use a hand blender to froth up the soup and arrange in bowls. Garnish with pretzel, pretzel crumbs, pesto and basil leaves
With 6 people: