In the bowl of a stand mixer, add all the crust ingredients and beat together starting on low. Scrape down the sides as necessary and gradually increase the speed until the dough comes together into a relatively cohesive ball; it should resemble Play-Doh. It will take a while, so don't be worried if it seems to spend a while looking like wet sand that will never come together.
Grease a 9" tart pan with cooking spray, and add the dough ball to the center of the pan. Press the dough down into the pan, spreading out out to the edges and up the side. Make sure it's pretty thin (~1/8"), and expect there to be some extra, so just trim that off the edges with a sharp knife. Once the crust is prepped, place in the fridge while preparing the filling.
Preheat the oven to 375°F.
Once again in the bowl of a stand mixer, add the butter and sugar for the filling and beat together until fully mixed and fluffy. Add the almond extract and mix until combined. Add the eggs one at a time, mixing well between each until fully combined.
In a small bowl, combine the almond flour, all-purpose flour, 1/2 tsp cinnamon, 1/8 tsp allspice, and 1/8 tsp nutmeg and whisk to combine. Pour the dry ingredients into the wet mix and fold together until completely mixed.
In a small bowl, combine the apple slices and the apple spices, and toss until all the apple slices are coated.
Remove the tart crust from the fridge and pour the filling into it, spreading it to the edges and smoothing it with an offset spatula. Arrange the apple slices on top as seen in the photo, to resemble Shai-Hulud rolling through the sands of Arrakis. Or make any pattern you'd like!
Place the filled tart in the oven and reduce the temp to 350°F. Bake for 40-50 minutes until the top is browned and set. Remove from the oven and let it cool for at least 15 minutes before removing from the tart pan and serving.
Enjoy!
