PENNSYLVANIA DUTCH BEEF WITH ONIONS

PENNSYLVANIA DUTCH BEEF WITH ONIONS
* 1½ lbs. boiled beef
* 2 tablespoons butter
* 1 tablespoon vinegar
* 1 onion
* 2 tablespoons flour
* 1 pinch of pepper
* ½ cup meat stock
* salt

Mince the onion. Simmer in butter until soft. Add flour and simmer until brown. To this add vinegar, salt, pepper and meat stock and let come to a boil. Cut the meat in slices and serve hot, with the onion sauce.