Preheat oven to 350° F.
Butter a 9-inch round pan with removable bottom and line with parchment paper.
To make crust:
In a medium bowl, combine the flour, sugar, baking powder and salt. Mix well.
Add the butter and cut it in to form crumbs. Add the egg and combine until dough starts coming together.
Add the crust mixture into the prepared pan and spread it out evenly.
Bake for about 20 minutes, or until it puffs up, then settles down and browns a bit.
Remove from the oven and let cool. Do not turn off the oven.
To make the crumble (topping):
While crust is cooling, in a medium bowl, add the flour, sugar, brown sugar, and cinnamon and mix well. Cut in the butter until pea-sized.
Add the pecans and combine until crumble mixture is starting to clump. Set aside.
To make pumpkin filling:
In a medium bowl, combine pumpkin, sugar, salt, and spices together with a spatula.
Add the egg and mix until incorporated well.
Add milk and stir to a smooth consistency.
Pour over cooled crust, and gently sprinkle the crumble evenly over the filling mixture.
Bake until set, about 40 minutes.
Cool completely before removing from pan. You can remove the dessert from the removeable pan bottom carefully, once fully cooled, and more successfully if you've lined the pan with parchment.