The shell:
Beat egg whites, salt, and vinegar until soft peaks form.  Blend the sugar and the cinnamon, and gradually add them to the egg white mixture,  beating until very stiff peaks form and all sugar has dissolved. Draw a plate-sized circle on a piece of heavy paper. Spread mixture within the circle, making the bottom 1/2" thick and molding  the edges to 1 3/4" high. For decorative trim, form ridges on the outside of rim with the back of a teaspoon. Carefully place in preheated oven and bake at 275ºF. for one hour Turn off heat and let dry in oven (door closed) about two hours. Carefully peel shell from paper.
The filling:
Melt the chocolate over hot, not boiling water. Cool slightly, then spread 2 tablespoons of the  chocolate over the bottom of the cooled meringue shell. To the remaining chocolate, add egg yolks and water. Blend together. Chill until mixture is thick. Combine cream, sugar, and cinnamon, whipping until stiff.  Spread half over chocolate in shell. Fold remainder into chocolate mixture. Spread on top of shell. Chill several hours, or overnight. For serving, trim with whipped cream and sprinkle with pecan pieces. Serves 8-10