Preheat your oven to 350° Fahrenheit and line a baking dish with parchment paper. I used an 8x8 inch glass dish.
Place your nuts and almond flour in your food processor and pulse until the nuts are fine in texture, similar to the almond flour. You don't want any chunks of nuts, but be cautious of over-pulsing as you will start to turn the nuts into nut butter.
Next, place the nuts in a mixing bowl and combine the rest of the crust ingredients. Mix everything together until the ingredients are fully incorporated.
Pour the crust into your parchment lined baking dish and use your hands or the back of a spoon to spread the crust out evenly. You'll want to press it down and pack the crust a bit. Set the crust aside for a few and prepare your pumpkin pie filling.
Place your almond flour and spices (leave out the baking soda for now) in a small mixing bowl and whisk them together.
Next, whisk your egg in a separate mixing bowl and then add the rest of the wet ingredients (except for the apple cider vinegar - you'll use it in the last step of making the filling). Continue whisking until all of the wet ingredients are smooth and combined.
Slowly add the bowl of dry ingredients, whisking as you do until the flour and spice mixture is evenly incorporated into the wet ingredients.
Next, add your baking soda and apple cider vinegar. It will get fizzy and then you'll stir it into the batter.
Pour the pumpkin pie filling right over your crust.
Place your soon-to-be pumpkin pie bars in the oven and bake at 350 degrees for about 45 minutes, or until a toothpick comes out clean. Remove your pumpkin pie bars from the oven and let them cool completely. They will firm up a bit as they cool. I like to put them in the fridge once they've cooled mostly and let them firm up even more before cutting them into bars.
Once they are cooled and you are ready to serve your bars, pull the parchment paper from your pan and place your lovely pumpkin pie bars on a cutting board.
Cut your pan-sized treat into squares and serve them up! You can store them in an airtight container in the fridge for about a week, or freeze them for longer.