How to Make It
Preheat oven to 350°F. Lightly grease a 9x13-inch baking dish with butter or non-stick spray.
Make the base. In a large bowl, whisk together pumpkin, sugar, cream, chocolate, eggs, cinnamon, cloves, and salt. Pour into baking dish.
Make the cake mix. Combine flour, chocolate, sugar, cocoa powder, baking powder, baking soda, and salt in a medium bowl and sprinkle evenly over the base. Using the largest holes on a box grater, grate the butter evenly over the surface of the cake.
Bake until cake is set around the edges but still wobbly in center, 45 to 50 minutes. Cool 30 minutes before serving.