Heat oven to 325°F. In ungreased 13x9-inch (3-quart) glass baking dish, arrange beef in single layer. Top with carrots and onion.
In medium bowl, mix tomatoes and gravy; spoon over beef and vegetables. Cover with foil; bake 2 hours.
In 3-quart saucepan, make both pouches of potatoes as directed on box using water, milk and butter. Stir in egg until well blended.
Remove baking dish from oven. Uncover; spoon or pipe potato mixture over hot mixture. Return to oven; bake uncovered 15 to 20 minutes longer or until potatoes are set and light golden brown.