2 bottom round roasts, thinly sliced
1 envelope Italian dressing mix
1/2 cup beef bouillon
1/2 cup cider vinegar
1/4 cup olive oil
Freshly ground pepper
2 large onions, sliced
Place beef slices in the pressure cooker. Sprinkle with the dry Italian dressing. Add bouillon, cider vinegar, olive oil, pepper and onions. Pressure cook on high for 15 minutes. Let pressure release naturally.
Dip meat out with a slotted spoon onto sub buns. Top with pepperoncini and a little sour cream.