Wash a lettuce, trim off the outside leaves, tie with tape and blanch for a few minutes in boiling water, and allow to drain. When cool, split each with a sharp knife down one side, carefully remove a small portion of the heart, and proceed to stuff them with a savory mince made as for rissoles, and bound with an egg. Then bring the severed edges of the leaves together so that the lettuces assume their former shape, tie them up again, and braise very gently with soup, vegetables and good stock for an hour, and serve with the stock thickened and poured over them.