Melt the butter along with the olive oil until almost smoking. Season the Medalions with salt and pepper. Place the medalions in the pan and saute for three minutes on each side for rare to medium-rare, longer if you prefer more done. Remove medallions from pan to a heated plate and set aside. Degrease the pan and add the garlic and saute until aroma is apparent about one minute, deglaze the pan with the brandy and port wine.
Cook stirring constantly for two minutes add the tomato wedges, scallions, parsley, and demi glace.
Bring to a boil and reduce heat, simmer for about five minutes return the medallions to the pan and reheat. Arrange medallions on a heated serving platter and pour sauce over and garnish with the minced scallions and parsley.