Pre-heat oven to 350 degrees. Prepare a 9-inch square or spring-form cake pan.
Add the topping ingredients to a small bowl, and cut in the butter, mixing with two forks until the mixture resembles coarse crumbs. Set aside.
Cake Batter
In a large mixing bowl, combine dry ingredients and mix to combine.
In a medium-sized bowl, stir the cooled melted butter, cream, and eggs until they are well combined.
Add the pumpkin puree to the wet mixture and combine until well incorporated. Then fold the wet mixture into the dry ingredients. Mix thoroughly until combined.
Spread the batter into the pan. Add the topping over the cake and pat gently into the batter.
Bake the cake for for 30-35 minutes or until the crumbs are lightly browned and an inserted toothpick comes out clean.
Cool the cake for 20 minutes.
Icing
In a small bowl mix the icing sugar with enough cream to make it pourable.