Spray a 8-inch (or 9-inch) cake pan with cooking spray (Pam) and flour and paper pan.
Combine cinnamon, orange zest, grated chocolate, and ground almonds in a mixing bowl and set aside.
In a seperate bowl beat egg yolks with 1/4 cup sugar, and then stir in orange juice. Set aside.
In another bowl beat egg whites to soft peaks while gradually adding the remaining 1/4 cup sugar.
Stir egg yolk mixture and orange juice into the chocolate/almond mixture. Fold in half of the beaten egg whites, blending well and then fold in the remaining egg whites.
Spread mixture in prepared pan and bake for 35-45 minutes or until done (when cake starts to pull away from pan). Let cake cool for 10 minutes before inverting onto a wire rack.
To make chocolate glaze: place chocolates (bittersweet and unsweetened), 1/2 cp of the butter, corn syrup and water in a double boiler over simmering water, stirring until melted. Remove from heat and stir inthe remaining butter (1/4 cup). The glaze is ready to pour of spread on cake when it is warm and is about as thick as syrup.
Place cake on dish and pour glaze over cake, tilting to coat evenly. Decorate with candied orange peel if desired.