01 -  Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, allowing some to hang over the edges for easy removal. 
 02 -  In a large mixing bowl, cream together butter and granulated sugar until pale and fluffy. Add flour and salt, and mix until a soft dough is formed. 
 03 -  Press the dough evenly into the bottom of the prepared pan. Bake for 15 minutes, until slightly golden. Remove and let rest. 
 04 -  Combine diced apples, brown sugar, flour, cinnamon, nutmeg, and lemon juice in a bowl, tossing until well coated. Layer apple mixture evenly over the warm crust. 
 05 -  In a medium bowl, whisk together flour, brown sugar, granulated sugar, cinnamon, and salt. Add cold cubed butter and cut in using a pastry cutter or fork until mixture forms coarse crumbs. 
 06 -  Sprinkle crumb topping evenly over apples. Return pan to oven and bake for 30 minutes, or until the topping is golden and apples are tender. 
 07 -  Allow dessert to cool completely in the pan. Lift out carefully using the parchment paper overhang and slice into squares.