After the earthquake: Tranquil lettuce soup

After the earthquake, we needed something calming to eat, and my thoughts turned to lettuce. It has a venerable reputation, going back at least as far as the Romans, for promoting sleep, because the milky sap which provides its distinctive taste contains a minute quantity of something known as "lettuce opium". But the concentration is only 2 to 10 parts of morphine per million, compared with the usual therapeutic morphine dose of  0.5 to 50 parts per thousand - roughly a million times as much. So some hopeful hippies' attempts to get high on lettuce products were doomed to fail.

The French continue to regard lettuce as calming, especially when it's cooked. Elizabeth David has the perfect recipe for trying this out: Potage du Père Tranquille, Soup of the Tranquil Father. She explains that he "seems to have been a somewhat mysterious Capuchin monk, but the name ... is also a reference to the supposedly soporific effects of lettuce."

It also feels very economical, because it can be made with the outside leaves of lettuce that are usually thrown away. In The Colour of Food, I tell a story about this:

Every so often Harvey would embarrass me by well-meant but misplaced praise – like the time he announced proudly to a well-to-do guest who had arrived at short notice, ‘Anne made this soup from the outside leaves of lettuce!’ Even though Potage du Père Tranquille was a good French recipe, I cringed at having my economy exposed.

I doubt that the French ever use iceberg lettuce, but it works perfectly well for this soup, and one large lettuce provides enough outer leaves for the recipe.

Potage du Père Tranquille - Tranquil Lettuce Soup 
(Adapted from Elizabeth David, French Provincial Cooking)
Makes 4 generous servings or six smaller ones

Outer leaves of one large iceberg lettuce or 2 to 3 buttercrunch ones (David says 3)
(If you have lots of lettuce to spare, use a whole one)
500 ml mild chicken stock (I use half chicken and half miso stock)
300 ml milk
salt and pepper
about 1/8 tsp grated nutmeg
1 tsp sugar
small lump of butter or 50 ml cream

- Wash leaves carefully, shake off water, pile them together and slice them across into long fine ribbons.

- Put the sliced lettuce in a large sauce[an with just enough stock to cover them. Simmer gently, adding a little more stock or water if necessary, until they are quite soft.

- Drain the cooked lettuce through a sieve into a bowl. Keep the bowl of stock.
- When the lettuce has cooled, puree it in a blender or food processor.
- Return the puree to the pan. Stir in the stock and enough milk to make a thin cream (check the flavour after adding some milk, as you do not want to make the soup too bland and tasteless).
- If you don't want any little bits of lettuce in it, sieve the soup at this point. (I rather like the texture and colour of the tiny green bits.)

When you're ready to serve the soup:
- Add sugar, a good grind of black pepper (or if you do not want to see black specks, white pepper) and a small grating of nutmeg. Taste for seasoning and add salt only if necessary.
- Gently reheat soup and just before serving, stir in either a small lump of butter or a little fresh cream.

French bread is good with this, but so are garlic bread or Vogel's Extra Thin.
I don't know if it did indeed make us more tranquil, but it certainly felt soothing and warm on the stormy day after the earthquake.