FOR CAKE: Preheat the oven to 325° F. Grease 10-inch Bundt pan.

Combine the flour, baking soda and baking powder in a small bowl. Bring the water and coffee granules to a boil in small saucepan and remove from the heat. Add 3 bars (6 ounces) of baking chocolate to the pan and stir until smooth.

Beat the sugar, butter and vanilla extract in a large mixer bowl until creamy. Add the eggs and beat on high speed for 5 minutes. Beat in the flour mixture, alternating with the chocolate mixture.

Pour the batter into the prepared pan and bake for 50 to 60 minutes or until long wooden pick inserted in cake comes out clean. Cool in the cake in the pan on a wire rack for 30 minutes. Invert onto wire rack to cool completely. 

FOR CHOCOLATE GLAZE: Melt the remaining baking bar (2 ounces) and butter in small, heavy-duty saucepan over low heat, stirring until smooth. Remove from the heat. Stir in confectioners' sugar, alternating with the water until of desired consistency. Stir in the vanilla extract.

Set the cake on a rack positioned in a jelly-roll pan to catch the excess glaze. Pour the glaze over the cooled cake, letting it slide down the sides of the cake. Sprinkle with confectioners' sugar and then let the glaze set before serving.