Brown veal quickly, a few pieces at a time, in butter or margarine in a large frying pan; sprinkle lightly with salt and pepper; remove and keep warm while making sauce.

Stir mushrooms and liquid and tomatoes into drippings in frying pan; heat to boiling, scraping browned bits from bottom of pan, then cook 5 minutes, or until sauce thickens slightly. Place veal in sauce; heat slowly 1 minute, or just until hot. Spoon onto serving plates.