Combine soup and cheese in a large sauce pan; heat slowly, stirring until cheese melts completely, remove from heat. Stir in rice, tuna and pepper. Beat egg yolk in a small bowl; slowly stir into tuna mixture. Beat egg whites until they form firm peaks in a small bowl; fold into tuna mixture until no streaks of white remain.

Pour into an 8x8x2 baking dish spreading top evenly, bake for 40 minutes in a 350 degree oven.

Serves 6 (it will puff up and brown then fall some when you take it out of the oven, let it cool for 5 minutes before cutting).