Two ounces of butter or good dripping. Salt and pepper.
Soak the lentils in cold water overnight. Melt the butter in a saucepan; if possible, use only the red part of the carrots, cut the carrots and leeks into thin shreds, add them and the lentils to the butter, toss them about in it until the butter is absorbed, but be careful the vegetables do not brown. Add the milk-and-water, and boil gently until the lentils and carrots are soft-they will probably take an hour, or even longer.
Rub the soup through a hair sieve, rinse out the pan, pour back the soup, and let it boil. Then add the cooked rice and the lettuce, having first well washed it and cut it into shreds. Season it carefully, and serve in a hot tureen.
Cost, about 1s.