Cut mamey in half lengthwise: remove and discard seed. Cut fruit lengthwise into 24 1/2 inch slices; set aside.

Combine milk, rum, 2 tsp sugar, and egg yolks in top of a double boiler; bring water to a boil. Reduce heat to low; cook 2 minutes or until thickened, stirring constantly. Pour into a medium bowl; stir in vanilla. Let cool to room temperature.

Beat egg whites (at room temperature) until soft peaks form; add remaining 2 tsp surgar, beating until stiff peaks form. Gently fold egg whites into yolk mixture.

Arrange 3 mamey slices on each dessert plate; top each with 1/4 cup of topping and remaining slivered almonds.

Approx 110 calories per serving.