Snap off tough ends of asparagus and discard. Cook asparagus in boiling water until crisp-tender, about 6 to 8 minutes. Drain and pat dry. Place in a greased baking dish.
Melt butter in a medium saucepan. Add flour and whisk and cook for 1 minute.
Add bouillon granules and gradually whisk in half-and-half.
Bring to a simmer, whisking constantly and cook until thickened.
Remove from heat and stir in paprika, salt, and nutmeg.
Add cheese and whisk until completely melted.
Pour Mornay sauce over asparagus and season with a little black pepper.
Sprinkle crushed crackers on top.
Broil just long enough to warm sauce back up and get crackers golden. (Warning: crackers will burn very quickly. Keep an eye on it.)