Jamaican Chocolate Cake

Preheat oven to 325F (165C). Generously grease a 5-cup fluted or plain tube pan and dust lightly with flour. Sift flour, baking powder and spices into a bowl. Add margarine, superfine sugar and eggs. Blend cocoa powder with hot water and add to flour mixture. Beat well with a wooden spoon 2 minutes or 1 minute if using an electric mixer. Turn mixture into prepared pan. Bake in preheated oven 1-1/4 hours or until well risen and cake begins to shrink from edges of pan. Carefully turn out cake onto a wire rack and cool. Combine granulated sugar and 2/3 cup water in a saucepan. Add cinnamon and heat gently, stirring to dissolve sugar. Boil 5 minutes. Add rum, remove from heat, and discard cinnamon; let cool slightly. Place cake on a plate. Spoon syrup over cake and let stand 2 hours. Melt chocolate; carefully spooon over cake, spreading to give a smooth even coating. Let stand refrigerated several hours, or overnight. Drizzle with white chocolate, let it set, and serve.