Teriyaki sauce gives its own particular flavor to any dish, so this recipe is good when using pork medallions. This dish then depends for the bulk of its flavor on the marinade. This procedure is best done in a plastic “zip-lock” bag, into which you place the pork and the marinade. Turn it over several times to let the marinade get on all sides and then place in the refrigerator for at least one hour, but three or four is better. It is very simple to cook after the marinade process.
Combine the marinade ingredients in a small bowl. Place pork in a Ziploc bag and pour marinade over pork. Marinate for at least one hour in the refrigerator.
Remove from the marinade and place pork on heavy duty aluminium foil. Season with salt and pepper. Arrange onion slices over pork. Seal edges of aluminium foil and place on grille at medium heat. Grill for 20 minutes turning once or twice.