Melt butter in 10-inch skillet over medium heat. Add onion; cook and stir until tender. Arrange about half of the asparagus spears in spoke-fashion, tips pointing out, over cooked onion. Beat eggs in large bowl. Add milk, 3/4 cup of the cheese, salt, basil and pepper; blend well.

 

Slowly pour egg mixture over asparagus in skillet. Reduce heat to low. Cover and cook 16 to 18 minutes or until egg mixture is set.

 

Arrange remaining asparagus spears in spoke-fashion over egg mixture. Arrange tomato slices in center; sprinkle with remaining 1/2 cup cheese. Remove skillet from heat. Cover; let stand 5 minutes or until cheese is melted. Cut into wedges to serve.