In large bowl, combine all ingredients excepts olive oil, mushrooms and instant gravy. Hand knead until all ingredients are well mixed. Form mixture into oval patties about an inch thick and about 5 inches long. Fry in olive oil until browned on the outside but still uncooked inside. Arrange browned patties in glass or aluminum baking dish.
Drain mushrooms, retaining liquid. Add enough water to the mushroom liquid to equal the amount needed for gravy, and prepare gravy according to package directions. When gravy has thickened, add mushrooms and pour over patties. Cover dish with foil and bake at 350°F for 1 hour. Check patties with meat thermometer; center should register 165°F. Cook longer if necessary until temperature is reached.
James Wiggins Rome, OH