Cook asparagus as directed on package until barely tender; drain.
In a large skillet, cook onion in butter until tender (not brown). Stir in flour. Add milk and cook, stirring constantly, until thickened. Mix in salt, pepper, eggs, and asparagus.
Turn into a 2-qt. casserole. Top with cheese and crumbs. Bake in moderate oven (350°) about 30 minutes, unti