Heat oven to 350°F. Spray 8-inch square (2-quart) glass baking dish with cooking spray. In 8-inch skillet, cook sausage over medium heat 8 to 10 minutes, stirring occasionally, until no longer pink.
In baking dish, layer half of the thawed potatoes, half of the Colby-Monterey Jack cheese, the cooked sausage, thawed asparagus, remaining potatoes and cheese.
In medium bowl, beat eggs and milk until well blended. Pour evenly over potato mixture.
Cover tightly with foil; bake 1 hour. Uncover dish; sprinkle with Parmesan cheese. Bake uncovered 15 to 20 minutes longer or until knife inserted in center comes out clean. Let stand about 5 minutes before serving.