Ingredients
Equipment
Method
Preheat and prep crust
- Preheat the oven to 375F. Fit the unbaked 9-inch pie shell into a 9-inch pie dish and crimp the edges, then place the pie dish on a sheet pan for easier handling.
Make the apple filling
- Toss the sliced apples with granulated sugar, cinnamon, nutmeg, cornstarch, and lemon juice until evenly coated. Pile the apples into the unbaked shell and mound slightly so the filling bakes up higher.
Make the oat crumble
- Combine rolled oats, all-purpose flour, brown sugar, cinnamon, and salt in one mixture. Cut in the cold cubed butter until chunky clumps form.
Assemble and bake
- Scatter the oat crumble topping over the apple filling and cover generously. Bake for 55-65 minutes at 375F until the crumble is deeply golden and you see bubbling at the edges.
- Tent the pie loosely with foil after 35 minutes if the topping browns too quickly. Continue baking until the total bake time is reached and the filling bubbles through.
Cool and slice
- Cool the pie for at least 1 hour before slicing so the filling sets. The crumble should feel firm and the apple juices should thicken rather than run.
Notes
For cleaner slices, let the pie cool until mostly room temperature, then slice with a sharp motion. Store covered in the refrigerator up to 4 days; reheat individual slices in the oven at 325F for 10-15 minutes to re-crisp the crumble. Freezing is not recommended because the crumb and crust texture can soften after thawing. For a lower-sugar option, replace the granulated sugar and brown sugar with a 1:1 baking sweetener blend and expect a slightly less dark crumble.