Apple Crumb Pie Bars

Makes 9 bars 

Pastry 

1 cup unbleached all-purpose flour, plus more as needed 

1 tablespoon granulated sugar 

¼ teaspoon kosher salt 

6 tablespoons unsalted butter, cold, cut into tablespoons, plus more for the pan 

1     large egg yolk 

2½ teaspoons ice water 

¼    teaspoon grated lemon zest 

¼    teaspoon pure vanilla extract 

Crumb topping 

¾    cup plus 2 tablespoons unbleached all-purpose flour 

6     tablespoons packed light brown sugar 

1     teaspoon ground cinnamon 

        pinch kosher salt 

½     teaspoon pure vanilla extract 

6      tablespoons unsalted butter, cold, cut into tablespoons 

Filling 

3      large apples (Honeycrisp, Ginger Gold, Granny Smith), peeled, cored, and halved,                 cut to fit the feed tube 

⅓ cup granulated sugar 

       juice of ½ lemon 

1    teaspoon pure vanilla extract 

1.Prepare the pastry: Put the flour, sugar, and ¼ teaspoon of salt in the work bowl fitted with the metal chopping blade. Process to sift for about 10 seconds. Add the butter and pulse about 6 times to evenly incorporate. Add the egg yolk pulsing to incorporate. Add the water, lemon zest, and vanilla and pulse an additional 3 to 4 times to incorporate. 

2.Remove and shape into a round, flat disc. Wrap in plastic and allow to rest for at least an hour or up to 3 days in the refrigerator. 

3.Prepare the crumb topping: Put the flour, brown sugar, cinnamon, and pinch of salt in the work bowl fitted with the metal chopping blade. Process to sift for about 10 seconds. Add the butter and quickly pulse to incorporate, 6 to 8 pulses. Transfer the mixture to a medium bowl. Use your hands to mix the ingredients and create large clumps. Reserve. 

4.Wipe out the work bowl and insert the slicing disc. Slice the apples. Transfer the apples to a medium bowl and toss with the sugar, lemon juice, and vanilla. 

5.Preheat the oven to 350°F. On a lightly floured surface, roll the pastry to a large square, about ⅛ inch thick. Lightly butter the bottom of a 9-inch square pan. Carefully transfer the pastry to the pan so that the pastry goes slightly up the sides of the pan, be sure that the dough is lightly pressed into the corners. If desired, trim the dough to create an even border, about ½ to 1-inch up the sides of the pan. Line with aluminum foil and pie weights. Blind bake for about 25 minutes, until lightly golden.  

6.Remove the foil. Layer the apple slices over the pastry and then top with the crumb topping mixture. Return to the oven and bake until the topping is lightly golden and firm and the apples are cooked through when tested with a paring knife, about 45 minutes. 

7.Cool completely before slicing and serving.