Take some peas and cook them in very little water and a piece of butter. Put in also the heart of a lettuce cut in four pieces, four or five small button onions, salt and pepper, and two rashers of bacon cut in small pieces. The best for this is not the ordinary bacon, but the kind known as “green” bacon, or pickled pork. If at the end of the cooking the sauce is getting a little short, add a small quantity of hot water; see that it is properly seasoned and serve at once. In Périgord they use pork fat instead of butter.