Using a vegetable parer, scrape across chocolate to make curls; refrigerate until needed. Loosely grate remainder of chocolate bar and refrigerate until ready to garnish.
Combine cherries with kirsch; let stand 1 hour. In small saucepan, mix cornstarch with cherry juice. Bring to a boil, stirring constantly; simmer 5 minutes until thickened. Let cool; add cherries and stir well to mix.
Prepare three 8-inch-diameter layer-cake pans by greasing and flouring.
Preheat oven to 350°F.
In large bowl of electric mixer, beat eggs at high speed until light. Add 1 cup granulated sugar gradually, beating well after each addition. Beat 10 minutes or until very thick. Add vanilla.
Sift sifted flour with cocoa; fold into egg mixture in fourths, using a wire whisk or rubber spatula. Fold in butter, in fourths, until just combined. Gently turn into prepared pans. Bake 15 minutes or until surface springs back when pressed with finger.
Place pans on wire rack and cool 5 minutes; remove from pans and cool completely.
In a small saucepan, stir granulated sugar and 1/2 cup water over medium heat to dissolve sugar. Bring to boil and boil 5 minutes. Cool, and stir in kirsch.
Using a skewer, make several holes in each cake layer; drizzle syrup over layers.
Beat heavy cream with confectioners’ sugar until stiff.
Invert one cake layer onto serving plate; spread with glazed cherries; top with 1 cup whipped cream. Top with second layer and 1 cup cream.
Add top cake layer; spread side and top of cake with whipped cream, decorating with 12 whipped-cream rosettes around top edge. Refrigerate cake.
Just before serving, arrange chocolate curls on top of cake and sprinkle side of cake with grated chocolate.