Apple Walnut Crisp
2 cans (21 oz each) apple pie filling
1 lemon
1 tsp ground cinnamon, divided
1 pkg (18.25 oz) plain yellow cake mix
1 cup chopped walnuts
1 cup (2 sticks) butter, melted
Place a rack in the center of the oven and preheat the oven to 325 degrees F for a glass pan or 350 degrees F for a metal pan. (Glass pans are better if you're planning on storing the dessert for longer than a day; after that a metal pan will begin to corrode.)
Spoon the apple pie filling evenly onto the bottom of an ungreased 13- by 9-inch baking pan. Grate the zest from the lemon and sprinkle it over the apples. Cut the lemon in half and squeeze the juice over the apples. Sprinkle the apples with 1/2 tsp cinnamon. Pour the dry cake mix evenly over the apples so that it reaches all the sides of the pan. Sprinkle the cake mix with the remaining 1/2 tsp cinnamon. Sprinkle the walnuts on top and drizzle the melted butter over the entire pan. Place the pan in the oven.
Bake the crisp until is is golden brown and bubbly and the walnuts have browned, 55 to 60 minutes. Remove the pan from the oven and place it on a wire rack to cool for 10 minutes.
Spoon the crisp into bowls, topped with a scoop of vanilla ice cream, and serve.