Gromperenzopp (Potato Soup)

Ingredients:

5 leeks
2 tbsp butter
5 potatoes, peeled and diced
750ml water, boiling
2 tsp sea salt
750ml milk, boiling
2 egg yolks whisked with 120ml cream (or sour cream)
salt and pepper, to taste
finely-chopped parsley, to garnish

Method:

Remove the roots and the green stalks from the leeks, wash thoroughly to remove any dirt then chop into small pieces. Melt half the butter in a heavy-based soup pot then add the leeks and fry slowly over low heat until the leeks are soft and transparent (about 8 minutes). Now add in the potatoes along with 750ml boiling water and 2 tsp salt.

Bring the mixture to a boil, reduce to a simmer and cook for 30 minutes. Take off the heat and cool slightly then either press through a fine-meshed sieve or pass through a food mill to purée. Return the purée to the pan then add the boiling milk, stirring constantly. Now stir in the remaining 1 tbsp butter.

Bring to a gentle simmer (but do not boil). In the meantime, whisk together the eggs and cream (or sour cream) in a heat proof bowl. Add a ladleful of the soup to temper and whisk to combine then slowly add the egg mixture to the soup. Heat until thickened, stirring constantly (but do not boil, or the soup will curdle).

Adjust the seasonings to taste, ladle into warmed soup bowls, garnish with the chopped parsley and serve.