Preheat and prepare your dish. Preheat the oven to 350°F and spray a 9x13 casserole dish with nonstick cooking spray.

Crush the cookies. In a food processor, pulverize the Oreo cookies to a fine, sand-like texture. This should only take about 1 minute.

Combine with butter. In a large bowl, combine the Oreo crumbles with ½ c (1 stick) softened butter, mix well until it’s a wet sand texture.

Press the crust into the pan. Press the Oreo crumble into the bottom of the casserole dish in an even layer to create the crust and use the bottom of a measuring cup or a flat surface to press the crumbles firmly. Place the dish in the freezer while you make the filling.

Make the cheesecake layer. In a large bowl, beat the powdered sugar and cream cheese together until smooth and creamy.

Pipe onto the crust. Place the filling into a piping bag or resealable plastic bag with the corner cut off and pipe the filling over the crust into an even layer. You can also use a rubber or offset spatula to even out this layer.

Top with the lemon layer. Pour the lemon pie filling over the cream cheese layer and smooth it to the edges with a rubber spatula.

Make the topping. In another large bowl, combine the remaining ½ cup (1 stick) softened butter with the cake mix. Use a fork or clean hands to crumble the cake mix into the butter. It will appear dry and not formable, that’s ok. Work the butter into the cake mix until it is evenly distributed and has a crumbly texture.

Sprinkle over the top. Sprinkle this crumble over the lemon pie filling, making sure it reaches all the way to the edges.

Bake. Bake uncovered for 50-60 minutes or until the crumble topping starts to turn a medium golden brown.

Cool, garnish, and serve. Remove the cake from the oven and allow it to cool slightly (or chill in the refrigerator) before serving with lemon slices and whipped topping.