Preheat the oven to 350°F. Spray a bundt pan with cooking spray.

In a large mixing bowl, combine the cake mix, pumpkin, eggs, and pumpkin pie spice and mix well. Take 1 cup of the batter and place it in a small mixing bowl.

Melt ⅓ cup chocolate chips in the microwave for 45-60 seconds or until mostly melted. Stir until smooth and glossy. Add the melted chocolate to the 1 cup reserved batter along with the cocoa powder.

Layer half of the pumpkin batter into the prepared bundt pan and top with the chocolate batter, spreading to cover the pumpkin batter. Top with the remaining pumpkin batter, smooth the top, and bake for 30-40 minutes or until a toothpick inserted into the center comes out clean.

Remove from the oven and let cool in the pan for 15 minutes, then place on a wire rack to finish cooling.

Place the remaining ½ cup chocolate chips in a heatproof bowl. Heat the cream until it just starts to boil. Pour over the chocolate chips and let sit for 5 minutes. Stir the mixture well until smooth and glossy. Stir in the vanilla.

Place a piece of waxed paper under the wire cooling rack and drizzle the chocolate mixture over the top of the cake. Let the chocolate cool before placing the cake on a serving plate or cake stand.