Leek Soup
1/2 pound leeks 1/2 pound potatoes 1 quart boiling water Salt and pepper 1 ounce butter Wash, and trim the leeks, and cut them into slices. Cut the potatoes into pieces about the size of a small walnut. Cook the vegetables for five minutes in the butter. Add the water, and cook until the leeks are tender and the potatoes break up--about one hour. Season and serve.
A plain potato-and-leek soup of the sweated-then-boiled school, with no stock, no cream and no blender. It works, but a few points of period shorthand are worth translating.
- Sweat, don't brownThe five minutes in butter is the only step that builds flavour, since there is no stock here. Keep the heat low and lid the pan so the leeks soften and release their sugars rather than colouring.
- An ounce of butterThat is 2 tablespoons, or 28 g. It is a modest amount for a quart of soup; adding another tablespoon at the end, off the heat, does more for the texture than doubling it at the start.
- Quantities and yieldHalf a pound each of leeks and potatoes with a quart of water gives roughly four small bowls or two generous ones. Weigh the leeks trimmed of their coarsest green, or you will end up short.
- Wash the leeks properly"Wash and trim" understates it. Slice first, then swish the rings in a bowl of cold water and lift them out, leaving the grit behind; rinsing a whole leek under the tap does not reach the layers.
- The hour is negotiableAn hour is longer than a modern hob needs; 25 to 35 minutes at a gentle simmer will usually have the potatoes collapsing. The point is the breakdown, not the clock.
- Potato choiceFloury potatoes (russet, Maris Piper, King Edward) will break up and thicken the water as intended. Waxy salad potatoes hold their shape and leave you with vegetables in hot water.
- Season late and hardWith water instead of stock, salt is doing all the work. Season only once the potatoes have disintegrated, taste, and expect to need more than you think. A little lemon juice or a grating of nutmeg lifts it without departing from the period.
- To finishLeft as written it is rustic and slightly ragged. Crushing it against the side of the pan with a spoon gives body; a full blitz turns it into something closer to a modern vichyssoise, which is a different dish.
Leek and potato soup is the standing example of cookery from the kitchen garden: two cheap keeping vegetables, water, and whatever fat the house had. The grander relative is vichyssoise, the chilled, sieved, cream-enriched version generally credited to Louis Diat at the Ritz-Carlton in New York in the early twentieth century, itself an elaboration of the same peasant pot. Leeks have carried a long association with Wales and with the poor man's kitchen; the medieval English kitchen used them constantly, and they survived into modern cookery largely as a soup vegetable.