In a large bowl, whisk together the flour, salt, and granulated sugar.

Add the solid coconut oil to the flour mixture and use a pastry cutter or your fingers to mix until the mixture resembles coarse crumbs.

Gradually add the cold water, one tablespoon at a time, mixing until the dough comes together. You may not need all the water.

Divide the dough into two equal parts, shape them into discs, wrap in plastic wrap, and refrigerate for at least 30 minutes.

In a small saucepan, combine the blueberries, maple syrup, cornstarch, and vanilla extract. Cook over medium heat until the blueberries break down and the mixture thickens, about 5-7 minutes. Remove from heat and let cool.

Preheat your oven to 375°F (190°C).

On a lightly floured surface, roll out one disc of dough to about 1/8 inch thick. Cut into rectangles (about 3x4 inches). Repeat with the second disc.

Place half of the rectangles on a baking sheet lined with parchment paper. Spoon a tablespoon of the blueberry filling onto the center of each rectangle.

Top each filled rectangle with another dough rectangle and press the edges to seal. Use a fork to crimp the edges for a decorative touch.

Bake for 20-25 minutes or until golden brown. Let cool slightly.

In a small bowl, mix the powdered sugar and almond milk until smooth. Drizzle over the cooled pop tarts.