Beat the eggs lightly in a bowl. Add the Gruyere cheese, shallots and broccoli; season with salt and pepper. Heat the oil in a large, heavy frying pan or skillet and pour in the egg mixture. Cook over gentle heat, lifting the edges to allow the uncooked egg mixture to run underneath. When the bottom of the frittata appears cooked and the top is lightly set, sprinkle with the Parmesan and broil until the cheese is golden.