Peel the potatoes and cut into cubes of about 1 cm.
Melt butter in a coated pan and roast the potatoes in it until they are cooked.
For the soup, bring 1 l of water to a boil.
Stir in sour cream. Reduce the soup a little with flour. Season to taste with spices, salt and pepper.
Add the roasted potatoes to the cream soup and serve.