1. Preheat the oven to 350°F (180°C). Grease and flour a 10-inch Bundt pan.
2. Cream the butter and sugar in the bowl of an electric mixer fitted with the paddle attachment for about 5 minutes, or until light and fluffy. Add the eggs, one at a time, then the orange zest.
3. Sift together 3 cups flour, the baking powder, baking soda, and salt in a large bowl. In another bowl, combine the orange juice, buttermilk, and vanilla. Add the flour and buttermilk mixtures alternately in thirds to the creamed butter, beginning and ending with the flour. Toss the chocolate chunks with 2 tablespoons flour and add to the batter. Pour into the pan, smooth the top, and bake for 45 minutes to 1 hour, until a cake tester comes out clean. Let the cake cool in the pan on a wire rack for 10 minutes.
4. Make the Syrup:
In a small saucepan over medium-low heat, cook the sugar with the orange juice until the sugar dissolves. Remove the cake from the pan, set it on a rack over a tray, and spoon the orange syrup over the cake. Allow the cake to cool completely.
5. For the Ganache:
Melt the chocolate, heavy cream, and coffee in the top of a double boiler over simmering water until smooth and warm, stirring occasionally. Drizzle over the top of the cake.
Makes 12 servings.
Date: April 19, 2004