Combine the ingredients for the lower crust, and mix them together, using your fingertips, until they make a course dough. Press this into a buttered 9″ x 12″ baking pan. Bake in a 325 degree oven for 25 minutes. Let Cool.
While this is baking, prepare the filling and the topping. For the topping, mix ingredients with your fingertips until crumbly. Set this aside.
To prepare the filling, combine the pumpkin, eggs and coconut milk. Blend well. Add all of the spices, sugars, vanilla and corn starch. Blend well.
Pour the pumpkin mixture on to the cooled crust. Gently sprinkle the topping all over the pumpkin layer.
Bake at 350 degrees for 55 minutes, or until set. Remove from the oven and let the pan cool on your counter. Once cooled, place in refrigerator for 30 minutes before cutting into squares.