Slit the chestnuts and bake or roast them for 20 minutes. Remove both skins and place them in a pan with the broth, using only just enough to cover them. Continue cooking the chestnuts until tender and almost dry, shaking to prevent burning.
Rub through a fine sieve, and add butter, salt, sugar and pepper. Add half a cupful of fresh bread crumbs and 1 beaten egg to bind the mixture.