Apple Pie (Maple with Walnut Crumble)

Apple crumble pie is the best of both worlds with a flaky crust and crumbly topping. This pie also has some maple syrup in the mix for added fall flavour.

Pie:
1 homemade or refrigerated pie crust
3 lbs baking apples, peeled, cored and sliced uniformly ¼" (I use a peeler/corer/slicer)
¼ cup light brown sugar
¼ cup cornstarch
2 Tbsp. pure maple syrup
1 Tbsp. lemon juice, freshly squeezed
½ tsp. ground cinnamon
¼ tsp. nutmeg, freshly grated
⅛ tsp. sea salt
1 egg, lightly beaten, for brushing the bottom crust
1 Tbsp. unsalted butter, cut into cubes

Topping:
¾ cup all-purpose flour, unbleached
½ cup granulated sugar
¼ cup light brown sugar
1½ tsp. ground cinnamon
½ tsp. sea salt
6 Tbsp. unsalted butter, cold, cut into cubes
½ cup walnuts, chopped

Preheat oven to 425°F (220°C/200°C fan, Gas Mark 7). Fit crust into a 9" pie pan and set aside.

In a large bowl combine the apples, brown sugar, cornstarch, maple syrup, lemon juice, salt, nutmeg and cinnamon. Give everything a toss and let stand for 15 minutes, stirring a few times.

Meanwhile, prepare the topping. In a medium bowl whisk together the flour, sugars, cinnamon, and salt. Cut in chilled butter using a pastry cutter or two knives until mixture resembles wet sand. Toss in walnuts and set aside.

Brush the crust with beaten egg and fill with the apple mixture. Make a decorative edge with overhanging bottom crust, if preferred. Scatter the butter over the top of the apples and cover with the topping.

Position a rack in the lower third of the oven. Cover the edges of the pie with foil or a pie crust shield.

Bake the pie for 30 minutes. Reduce the temperature to 350°F (180°C/160°C fan, Gas Mark 4) and bake another 30-45 minutes, until the topping is browned and the filling has begun to bubble.

Cool completely on a cooling rack, 3-4 hours, before slicing and serving.