Heat the oil in a large pan and fry the mushrooms until softened. Meanwhile melt the butter in another pan and stir in the breadcrumbs, Minced Garlic, Parsley and Parmesan. Arrange the mushrooms in an ovenproof dish and sprinkle with a little lemon juice. Top with the breadcrumb mixture and grill under a moderate grill for about 5 minutes until topping is brown and crispy.