In a large mixing bowl combine eggs, mushrooms, flour bread crumbs, onion, parsley, and pepper; mix well. In 10 inch skillet heat oil over medium-high heat. Using 1/3 cup mixture for each patty, shape mixture into approximately 3 1/2 inch patties. Using a spatula, place 4 patties at a time into hot oil in skillet. Cook 3 to 4 minutes per side until brown. Remove from skillet; drain on paper towels. Keep warm in oven. Cook and drain remaining patties.