Prepare the filling first, by heating blueberries and maple syrup in a small saucepan over medium heat. Bring to a simmer and continue cooking until blueberries begin to burst. Stir in tapioca starch and cook another 3-4 minutes, or until blueberry mixture begins to thicken. Remove from heat and set aside to cool.

Preheat oven to 350 degrees F.

Line a baking sheet with parchment paper and set aside.

Add almond flour, tapioca starch, and salt to the bowl of a food processor and pulse to combine. Add coconut oil or butter and pulse until a sand-like consistency.

Add egg and maple syrup. Process until a dough forms.

Transfer dough onto your work surface that has been lined with parchment paper or a silicone mat. Roll out dough to about 1/4-in thick. Cut into 8 5x3-in rectangles. Spoon 1-2 tablespoons of filling onto half of the rectangles, then cover with remaining half. Use a fork to crimp the edges together on all sides.

Transfer the pop tarts to the prepared baking sheet and bake 15-20 minutes, until golden. Cool.

To make the glaze, add coconut sugar and tapioca starch to a high power blender. Begin on low speed and gradually increase to high and blend until light and powdery consistency.

Transfer powdered sugar to a bowl and whisk together with blueberry filling.

Spoon glaze over each pop tart and allow to dry.

Store pop tarts in an air tight container for up to 5 days, or freeze for up to 3 months.