Position oven rack to the middle position of the oven and preheat the oven to 375 degrees F.
Lightly grease an 8 x 8 baking dish with coconut oil and line with unbleached parchment paper, leaving a 1-inch overhang on the sides. The parchment will make it easy to remove the bars from the pan.
Prepare the crust: process cookies and coconut oil in the bowl of a food processor fitted with the metal blade until it resembles wet sand. If you don’t have a food processor, you can smash the cookies into crumbs in a disposable bag and combine with the coconut oil in a large bowl. Transfer mixture to the prepared baking dish and press crumbs firmly into the bottom of the dish making an even layer. The crust should be about ¼-inch thick. You can use the bottom of a measuring cup to do this. The better you press the crust, the better it will hold together.
Bake the crust for 10 minutes, until just slightly browned. Remove from the oven and allow to cool. This can be done a day in advance.
Lower the oven temperature to 350 degrees F.
Prepare the topping: Pulse all the topping ingredients in a food processor or in the bowl of a mixer fitted with the paddle attachment. This can also be done by hand or with a pastry blender. The goal is to get the mixture to be moist, not dry, and in pea-size clumps. Squeeze with your hands to create small clumps. Place in the fridge to keep cold while you make the filling.
Blend all filling ingredients in a blender or whisk in a bowl and pour onto the prebaked crust.
Crumble topping evenly over filling. Bake until filling is set and the topping is golden, about 45 minutes. Allow to cool completely, cover and refrigerate. Can be made up to 3 days in advance. When ready to serve, run a thin knife around the perimeter of the baking dish and use the parchment overhang to lift out the bars.