Preheat the oven to 350°F (175°C). Butter a 9-inch (23cm) round pan with a removable bottom, then line the bottom with parchment paper.

To make the crust, stir together the cake flour, granulated sugar, baking powder, and salt in a medium bowl. Add the butter and cut it in until it’s the size of peas. Add the egg and stir until the dough starts to come together.

Dump the mixture into the prepared pan, then press it evenly into the pan. Bake for about 20 minutes, until it puffs up, then settles down and browns a bit. Remove from the oven but leave the oven on.

Meanwhile, make the topping. In a large bowl, stir together the all-purpose flour, granulated sugar, brown sugar, and cinnamon. Cut in the butter and add the pecans, then stir until the mixture starts to come together in clumps.

To make the filling, put the pumpkin, brown sugar, salt, cinnamon, allspice, cloves, ginger, and nutmeg in a medium bowl and stir with a whisk or spatula. Mix in the egg. Add the milk and stir until smooth.

Pour the filling evenly over the cooled crust, then sprinkle the crumble evenly over the top.

Bake for about 40 minutes, until the filling is set and the topping is golden. Let cool completely before removing from the pan.