Melt the butter and mix with the flour to make the roux. Pour on the sweet cream, add 2 liters of clear broth or vegetable broth (clear ones taste better to me), press 5 - 7 (depending on your taste) garlic toes onto it. Bring to the boil, stirring constantly. Salt and pepper.
If possible, let it steep for a day and only then reheat and serve.