Cook onions in butter until tender in 25 cm skillet over medium-high heat. Beat eggs with milk, salt, and pepper sauce. Stir in rice, tomato, and chilies. Pour into skillet. Reduce heat to medium-low. Cover; cook until top is almost set, dozen to 15 minutes. Sprinkle with cheese. Cover, remove from heat, and let stand about 10 minutes. Conventional Oven: Combine eggs, milk, salt, and pepper sauce in large bowl; whisk to blend. Stir in rice, tomato, cheese, chilies, and onions. Pour into greased 25 cm baking dish. Bake at 375 degrees 30 minutes or until knife inserted in center comes out clean.