Apple Walnut Crumble Pie

Method

For the crust

• In a food processor*, combine the flour, salt, sugar, and butter and pulse 4 to 6 times until larger than pea-sized butter pieces are still visible. Add 1 tablespoon (15 ml) of the cold water at a time, pulsing one or two times after each addition. Stop adding water and pulsing when you notice that the dough comes together and starts to clump.
• Without kneading the dough, form into a square roughly 3cm thick. Lift the left side of the dough and fold one-third of the dough over itself to create a section 2 layers thick. Then, take the right side of the dough and fold it on top so that it covers the previously folded left side of the dough, to make three layers. Using just your fingers, flatten the dough again into a 3cm thick square and fold it again into thirds. This time fold the side of the dough facing away from you and fold it towards you. Then fold the side of the dough facing to you, away from you in the same style as described above. Form into a dome, place in a bowl with a lid or plate on top. Refrigerate for at least 2 hours.

For the filling

• In a large bowl, stir the apples, lemon juice, brown sugar, cinnamon, flour, and vanilla to combine. Set aside.

For the topping

• In another large bowl, combine the flour, brown sugar, cinnamon, and butter. Use your fingers to work the butter into the dry ingredients until combined and pea-sized butter flakes are still visible. Don't overwork the butter, or it will become a paste. It should have a crumbly texture. Add chopped walnuts and combine. Place in the refrigerator until you are ready to sprinkle the topping on top of the pie.

Baking

• Preheat the oven to 200°C/180°C fan. After chilling the dough, on a lightly floured surface (or silicon sheet), roll out the dough into an 28cm even circle and transfer to a 25cm-ish pie dish. Evenly press the dough into the bottom and against the sides of the pie dish and flute the edges.
• Evenly spoon the filling with a slotted spoon or spider skimmer into the pie crust and discard any excess liquid from the filling if there is any. Sprinkle the crumb topping on top.
• Cover loosely with parchment and bake for 15 minutes. Then remove the parchment (reserve for later), let the pie in the oven, turn down the temperature to 190°C/170°C fan, and bake additional 30-35 minutes. Cover the last 15 minutes with the parchment again to prevent heavy browning if necessary. Remove from the oven and let cool to room temperature. Chill for at least 4 hours in the fridge for the filling to firm up if you can leave it that long.