Place Asparagus In A Steamer Basket Over 1 In. Of Boiling Water In A Saucepan; Cover And Steam Until Crisp-Tender, About 4 Minutes. Drain On Paper Towel. Place Crust On An Ungreased 12-In. Pizza Pan; Arrange Asparagus On Top. In A Bowl, Combine The Mayonnaise, Cheese And Mustard; Mix Well. In A Small Bowl, Beat Egg Whites Until Stiff Peaks Form. Fold Into Mayonnaise Mixture; Spread Over Asparagus. Bake At 450