PREHEAT OVEN TO 400°F Cook the asparagus in a pot of simmering water until tender, about 5 minutes. Drain and place in an ovenproof serving dish, then drizzle with the oil. Whisk together the milk, cheese, egg, egg white, and salt. Pour over the asparagus. Bake until the gratinata is browned and bubbling, about 20 minutes. Makes 4 servings.