With electric mixer, beat egg whites with salt, vinegar and 1/4 tsp. cinnamon until stiff. Gradually add 1/2 c. sugar. Spread over bottom and sides of cooled pie shell. Bake 12 - 14 minutes until lightly browned. Set aside to cool.
2Melt chocolate chips in microwave-safe container, stirring at 40 second intervals, until completely melted. Blend egg yolks with hot water, and stir into chocolate until smooth. Spread 4 or 5 tbsps over cooled meringue, and chill remaining chocolate until it begins to thicken - about 20 minutes.
3With electric mixer, whip cream til thickened, and beat in remaining sugar and cinnamon. Spread half over chocolate layer, and fold remainder of chocolate mixture into remaining half of cream mixture. Carefully spread chocolate blend over cream layer. Chill four hours.
Garnish with a big fluff of Cool Whip and drizzle with caramel ice cream topping. Also tasty (and pretty) topped with pecan halves and/or chocolate curls.