Position an oven rack in the bottom third of the oven. Preheat the oven (conventional) to 175℃ / 350 °F.

Grease the springform pan with butter and place a piece of parchment paper in the bottom of the springform pan. Close the springform pan and cut off all the baking paper that sticks out with scissors.

In a large mixing bowl, whisk together the self-raising flour, salt, and sugar.

Cut a part of the cold unsalted butter into small pieces, about ½ inch (1 cm) in size. Add this to the large mixing bowl. Make sure it is very cold.

Crack an egg and add it to the large mixing bowl. Add the vanilla extract as well. Knead the ingredients with your hands into a firm dough (you should no longer see pieces of butter).

Wrap your dough in cling foil. Place in the fridge for 30-60 minutes to rest. To allow the gluten to relax and the flour to fully hydrate.

In another mixing bowl add the all-purpose flour, granulated sugar, and unsalted butter. Knead this with your hands until crumble forms. Place the crumble in the fridge for about 30-60 minutes to rest.

Wait until the resting time is almost over with making the pear filling. Making and mixing it too early will draw out too many juices, which will make your crust soggy. Peel and core fresh pears. Then, cut into cubes. Place them into a mixing bowl.

Mix the pear with brown sugar, granulated sugar, cinnamon, pecan nuts, and vanilla extract.

When the resting time of the dough is over, you can lightly flour a clean work surface and place your dough on top. Lightly flour your rolling pin as well. Roll out the dough with a rolling pin and cover the bottom and edges of the springform pan with it.

Sprinkle half of the custard powder on top of the bottom crust. Add the pear filling on top of the crust. After that sprinkle some custard powder on top. As last add the crumble dough on top of the pear filling.

Bake the pecan pear crumble pie in the bottom third of the oven for 70 minutes at 175℃ / 350 °F. Place it on a cooling rack after baking. Allow the pie to cool completely before slicing it. This will allow the filling to completely thicken. Serve the pear crumble with a scoop of vanilla ice cream or whipped cream.