Mix the crumble ingredients together in a medium bowl. Place in the refrigerator.
Preheat the oven to 350 degrees.
Sift flour, corn starch, baking soda, baking powder, salt, cinnamon, ground cloves, ground ginger and nutmeg together. Set aside.
To a large mixing bowl add pumpkin puree, brown sugar, vegetable oil, maple syrup and milk. Whisk together then add the dry ingredients.
Pour batter into a parchment lined 9" pan.
Remove crumble topping from the refrigerator and break up with a fork. Spread evenly on top of the batter.
Bake for 35 minutes in the middle rack.
Remove from the oven and rest for 20 minutes before slicing into 9 pieces.