Lightly coat an unheated large nonstick skillet with cooking spray. Add asparagus to skillet and pan-roast over medium-high heat for 7 minutes or until browned and crisp-tender, turning occasionally. Cover with foil and set aside.
In a medium bowl combine egg whites and pepper. Using a fork, beat until combined but not frothy. In an 8-inch nonstick skillet heat oil over medium-high heat. Add egg whites to skillet. Reduce heat to medium. As eggs start to set, use a heatproof silicone spatula to gently lift edges of set egg white, tilting pan to allow liquid egg white to run under set egg. Continue until egg is set but still shiny.
Arrange the asparagus spears on half of the eggs in skillet. Top evenly with cheese. Fold the unfilled half of the eggs over the asparagus and cheese. Gently slide the omelet out of the skillet onto a serving plate. Sprinkle omelet with red sweet pepper slivers and parsley.
Variation: Salmon-Dill Omelet: Prepare omelet as directed, except omit the asparagus, cheese, parsley, and red sweet pepper. Fill omelet with ¾ ounce smoked salmon (lox-style) and 2 teaspoons finely chopped red onion. Top with 1 tablespoon plain nonfat yogurt and ½ teaspoon snipped fresh dill. Or, if desired, omit the fresh dill and stir a dash of dried dill weed into the yogurt and then spoon on top of the omelet. Per Serving: 104 cal., 3 g total fat (1 g sat. fat), 5 mg chol., 602 mg sodium, 3 g carb., 0 g fiber, 16 g protein. Exchanges: 2 lean protein, ½ fat. Carb choices: 0.