Fill the chilled crust with the completely cooled apple mixture, using a rubber spatula to scrape in all the thickened juices. The filling should look packed and glossy rather than watery.
Scatter about a cup or two of the crumble over the apples and return the rest to the fridge. Use enough to cover the fruit without burying it under the full batch too early.
Place the pie on the hot baking sheet and bake at 425 °F for 15 minutes. By the end of this stage, the crust edge should be starting to turn light brown.
Fold a square of foil into quarters, cut out the center, and open it back up to make a simple crust shield. The middle should stay open so the topping can continue to brown while the edges stay protected.
Lower the oven to 350 °F without removing the pie and continue baking for 10 minutes. This keeps the crust moving while the filling and topping bake more evenly.
Take the pie out briefly, add the remaining chilled crumble over the top, then set the foil shield around the crust edge. Cold crumble added partway through stays crisper and forms better clusters.
Return the pie to the hot baking sheet and bake at 350 °F for 25 to 35 minutes more, for a total bake time of about 55 to 65 minutes. The pie is ready when the crust is deep golden, the center topping is golden brown, and the filling is bubbling thickly.
Remove the foil shield for another 5 to 10 minutes if you want more color on the crust or crumble. Watch closely here so you gain browning without pushing the topping too far.
Cool the pie on a wire rack for about 4 hours before slicing. The filling sets as it cools, and the crumble stays crisp instead of collapsing into steam.