With A Rolling Pin, Roll Bread Flat; Cut With A 2-1/2-In. Biscuit Cutter. (Discard Bread Scraps Or Save For Another Use.) Press Bread Rounds Into Miniature Muffin Cups Coated With Cooking Spray. Broil 6 In. From The Heat Until Golden Brown, About 2-3 Minutes. Cool In Pans On A Wire Rack. In A Bowl, Beat The Egg, Egg White, Milk, Parsley, Salt, Baking Powder, Thyme And Pepper. Stir In The Broccoli, Cheese, Mushrooms And Onion. Spoon About 1 Teaspoonful Into Each Toast Cup. Bake At 350