Preheat the oven to 350°F. Lightly butter and flour a 6-cup Bundt pan. Set aside.
Place the butter in the bowl of an electric mixer fitted with the paddle. Beat on medium speed to just soften. Add the brown sugar and beat for about 4 minutes, or until very light and creamy. Reduce the speed to low and add the eggs, one at a time, beating well after each addition. Add the pumpkin and beat to blend.
Combine the flour, baking soda, cinnamon, nutmeg, cloves, and salt and, with the motor off, sift the dry ingredients into the pumpkin mixture. Turn the speed to low and beat to incorporate the dry ingredients into the pumpkin mixture. When well blended, remove the bowl from the mixer and, using a rubber spatula, fold in the chocolate, cranberries, and nuts.
Scrape the batter into the prepared pan. Bake for about 40 minutes, or until a cake tester inserted near the center comes out clean.
Remove from the oven and invert onto a wire rack. Remove the pan and allow the cake to cool to room temperature.
When cool, transfer the cake to a serving plate, placing the decorative side up. Place the confectioners’ sugar and cocoa powder in a fine-mesh sieve and, tapping gently on the side of the sieve, lightly dust the cake with the sugar-cocoa mix. Or, for a more elegant cake, omit the dusting and drizzle the cooled cake with Chocolate Glaze. Cut into slices and serve.
The cake will keep, covered and refrigerated, for up to 4 days or frozen for up to 3 months.
For the Chocolate Glaze:
Place the chocolate in a heatproof bowl. Set aside.
Place the cream in a medium heavy-bottomed saucepan over medium heat and bring to a boil. Immediately remove from the heat and pour over the chocolate. Let rest for a few seconds and then begin incorporating the cream into the chocolate by mixing with a rubber spatula.
When well blended, drizzle over the cooled cake. Let stand for a few minutes to harden slightly before cutting.