Remove outer leaves of romaine, separate stems from mushrooms and snap off tomato stems.
Break cauliflower into florets and trim stalk ends from asparagus.
Rinse all vegetables except mushrooms.
Wipe mushrooms with a damp paper towel.
Place inner leaves of romaine upright around the sides of a deep, round salad bowl.
Arrange remaining ingredients neatly in the center.
Cover and refrigerate to chill thoroughly before serving.