Engineered Cooking

1. Make the crust and topping: Heat oven to 350 °F. Line a 9-by-13-inch cake pan with foil with overhang on all sides. Lightly grease pan with softened butter.

2. Pulse flour, sugar and salt in a food processor with the blade attachment to mix. Add butter and pulse until mixture resembles coarse sand. Put 1½ cups in a medium bowl and mix in walnuts, cinnamon and cardamom. Squeeze with your hands to form a solid mass of dough. It’s O.K. if a few bits fall off. Cover and refrigerate.

3. Pour remaining mixture into prepared pan and spread in an even layer, then press into bottom of pan and ½ inch up the sides.

4. Bake until golden brown and dry to the touch, 20 to 25 minutes. Cool on a wire rack. Raise oven temperature to 375 degrees.

5. While crust bakes, make the filling: Toss all of the apples with the lemon juice in a large bowl. Melt butter in a large sauté pan set over medium-high heat. Stir in cinnamon, nutmeg and cardamom and sizzle for 15 seconds. Add apples and cook, stirring often, until just starting to soften, about 5 minutes. Add sugar and stir well. Cook, stirring occasionally, until all liquid releases from the apples then evaporates, 10 to 15 minutes. The mixture should be quite dry and the apples tender, but not sticking to the pan. Remove from heat and cool. (Tip: If you want your apples to cool quickly, spread them on a parchment-lined sheet pan and pop in the freezer for 5 to 7 minutes.)

6. Spread apple filling evenly over crust and press down gently to get rid of any gaps between the apple slices. Uncover the reserved walnut mixture and break off pebble-sized pieces. Arrange pieces in a lattice or striped pattern over filling or scatter evenly on top.

7. Bake until the topping is golden brown, 45 to 50 minutes. Cool completely in pan on a rack. To serve, lift apple pie bars out of pan and onto a large cutting board. Slide bars off foil, then cut into 6 even strips crosswise and 4 even strips lengthwise.