Prepare broiler.
Place the sliced asparagus in a small microwave safe bowl; cover. Microwave at high 20 seconds.
Combine milk and next 4 ingredients (milk through egg), stirring with a whisk.
Heat an 8-inch nonstick skillet coated with cooking spray over medium-high heat. Add beans and onion; sauté 30 seconds. Add egg mixture; reduce heat to medium, and cook for 1 minute. Sprinkle the asparagus and basil evenly over egg mixture, and cook for 1 minute. Sprinkle with cheese.
Wrap handle of pan with foil. Broil for 4 minutes or until top is set and cheese melts. Sprinkle with tomatoes.
