Prepare the sweetbreads as follows: wash and soak in cold water for 1–2 hr. until free from blood. Put into a pan, cover with cold water, bring to boil and simmer for 3–5 min., then plunge into cold water. Discard fat and skin and any gristle. Press between 2 dishes until cold. Roll in seasoned flour and coat with egg and breadcrumbs. Fry in hot fat until golden brown. Serve the sauce or gravy separately.