peeled and sliced mixed apples such as Cortland, Crispin, Golden Delicious, Ida Red, Jonagold, Spy)
1 1/2 tsp
cold unsalted butter, cut into small pieces
Aged Cheddar cheese slices for serving (optional)
To make pastry, place flour and salt in bowl of food processor. Pulse to combine. Add butter and pulse just until mixture resembles coarse crumbs with some pea-size pieces of butter remaining; do not over mix. In measuring cup, whisk egg yolk with vinegar then add enough ice water to bring mixture to 1/4 cup (60 mL). Gradually pour yolk mixture through feeder tube in top of food processor while pulsing to form a crumbly dough. Transfer to lightly floured surface and pat into 2 disks (pastry will still be crumbly; do not knead). Wrap each disk in plastic. Chill 1 hr.
Meanwhile, in large bowl make the filling by tossing the sliced apples with the sugar, flour, cinnamon and lemon juice. Set aside.
Preheat oven to 220°C (425°F). Roll 1 pastry disk on a lightly floured surface to 1/8-in. (3 mm) thickness. Line bottom, sides and rim of a deep dish 9-in. (23 cm) pie plate. Prick bottom with a fork a few times. Spread apple filling in pie shell, mounding in centre. Dot with the pieces of butter.
Whisk the egg with 1 tbsp (15 mL) water to make an eggwash; brush onto edges of the pie shell. Roll second pastry disk into 1/8-in. (3 mm) 12-in. (30 cm) round. Drape over filling. Press top and bottom edges together. Trim pastry. Crimp edges with fingers or press with tines of a fork. Brush pastry with eggwash. Use a sharp knife to cut 2 vent holes in the top.
Bake pie on lowest rack 20 min. then reduce temperature to 180°C (350°F) and bake another 50 min. to 1 hr., or until pie crust is golden brown and juices are bubbling. Transfer to a wire rack to cool completely. Serve with Cheddar cheese, if desired.
Pie dough can be made 24 hr. in advance, wrapped and refrigerated.