Paleo Blackberry Pop Tart Bars

2 Preheat oven to 325° and line a 9 inch square pan with parchment paper. Set aside.
5 Make the blackberry filling. Place the blackberries in a small sauce pan and add the maple syrup, lemon juice, and salt. Cook over medium/low heat, stirring regularly until berries have broken down, about 6 minutes. Mix the tapioca flour with a tablespoon of water to make a slurry and add it to the blackerries, stir until thickened, about another minute. Remove from the heat and let cool 10-15 minutes. 
3 Make the shortbread cookie. In a medium bowl, combine almond flour, coconut flour, salt, vanilla, maple syrup, and coconut oil. Stir together until it is well mixed and everything is incorporated evenly. Press 1/2 of the mixture into the bottom of the pan, top with the blackberry mixture and then top with the remaining shortbread. The best way to do this is take small pieces and press flat and then lay on top, pressing the edge of each piece together as best as possible. Bake for 35 minutes, until golden brown around the edges.
6 Make the frosting.  Place the blackberries in a small pan and cook over medium heat for 2-3 minutes, until cooked down and juicy. Strain through a fine mesh strainer and add the juice to a small bowl. Make sure the coconut butter is soft. You may need to microwave it for 30 seconds and stir first. Add that to the blackberry juice and add the maple syrup, lemon juice, water and salt. Stir until smooth. Pour it over the bars and place in the fridge to set. 
7 Store covered in the fridge for up to 10 days.