1. Preheat the oven to 400 degrees. Roll pie dough over a 9-inch deep-dish pie plate.
2. Dock the dough (prick with a fork) and blind bake for 10 minutes or until lightly golden.
3. Meanwhile, in a large bowl, toss the apples and pears with sugar, cinnamon, nutmeg and ginger. Transfer the apple mixture into a colander placed over a large bowl.
4. In a medium bowl, prepare the crumble by adding the oats, brown sugar, flour and salt. Use a fork or pastry cutter to cut in the butter until the butter is blended in and the mixture is clumpy.
5. Use a slotted spoon to transfer the apple mixture into the pre-baked pie crust, draining excess liquid.
6. Pile the crumble on top of the apples, pressing down into them gently to create a mound of the crumble topping.
7. Line a baking sheet with foil and place on the bottom rack of the oven to catch any drips if the pie cooks over. Reduce the temperature to 375 degrees.
8. Place the pie on the top shelf of the oven and bake for 1 hour and 15 minutes. Check on the pie after 45 minutes and tent the top with foil if it is browning too quickly.
9. Transfer to a wire rack to cool before slicing and serving.