Wash 150 grams leek and chop into rings of around 1 cm
Peel 1 clove fresh garlic and finely dice the garlic
Add 50 grams butter to a medium-sized saucepan and heat up over medium heat until the butter has melted
Add the leek and garlic to the medium-sized saucepan and fry in the butter for about 5 minutes while stirring occasionally
Peel 200 grams potatoes and cut them into cubes of about 2 cm
Add the chopped potatoes, 0.5 teaspoon salt, 0.5 teaspoon dried rosemary and 5 decilitres water to the medium-sized saucepan and bring the content to the boil
Cover the medium-sized saucepan with a lid and cook the vegetables for about 15 minutes until the potatoes are soft
Add 100 grams sour cream to the medium-sized saucepan and blend the soup with a hand blender
Add 1 decilitre water to the medium-sized saucepan, stir and simmer the soup for 2 minutes