Frankfurter Kressesuppe

Frankfurter Kressesuppe is spring soup from Hesse, the same green season that puts Grüne Soße on the table with eggs and boiled potatoes. I cook it when the garden cress in the little trays smells peppery before the scissors touch it. This is a weeknight bowl if you keep the potato base clean, and it can sit at a Sunday table before fish or a roast because it wakes the mouth instead of weighing it down.

Frankfurt uses Gartenkresse, garden cress, Schmand, sour cream, and potato for body. Along the Rhineland, you meet Brunnenkresse, watercress, sharper and more mineral, often held in a pale roux. Farther south, herb soups lean toward chervil, sorrel, and sweet cream. Im Norden anders, im Süden anders, different in the north, different in the south. The Frankfurt bite is cress.

The rule is simple: cook the potatoes, not the cress. Potato gives the soup body because its starch opens in the simmer and thickens without flour. Cress goes in raw at the end, off the boil, because hard heat drives off its peppery mustard bite and turns the green dull. Schmand is tempered off the boil too; boil sour dairy and it splits. Erst verstehen, dann kochen.

Use the leek white for the soup and the green for stock. Weggeworfen wird nichts, nothing gets thrown away. A powder cube makes the whole pot taste like the packet. Nicht aus dem Glas. Good stock, a floury potato, sharp cress, and enough salt at the end. That is the dish.