Place in a baking-pan a bed of vegetables cut in small dice, and a few pieces of salt pork. Lay parboiled sweetbreads on it. Add enough water or stock to cover the vegetables. Close the pan tight, and cook for forty to forty-five minutes. Uncover the pan the last fifteen minutes to let the sweetbreads brown. Paint them with glaze. Strain the liquor from the pan; thicken it with a brown roux, and serve it on the dish under the sweetbreads.