Asparagus with Ham Sauce

Melt butter in a saucepan, stir in flour, and cook for 3 or 4 minutes. Off heat, stir in milk; return to heat when smooth and cook until sauce thickens. Stir in purée chervil and minced ham. Be sure asparagus is hot. Chop 3 hard-cooked eggs and stir into sauce. Slice remaining egg. Garnish each serving asparagus with sauce and slices of hard-cooked egg.