Vegan Frosted Strawberry Pop Tarts

0 Make flax egg by whisking together flax seed meal and water, allow to set for 5 minutes. Line a baking sheet with parchment paper and set aside.
1 In a large bowl, whisk together the flour, sugar, and salt. Using a fork, your hands, a pastry cutter, or a food processor, cut in the butter until the mixture holds together when you squeeze it. In a small bowl, whisk together the prepared flax egg and non-dairy milk and add to the dough. Mix together until everything is evenly moistened. Knead the dough on a floured surface only for 1 minute to form a nice, smooth ball of dough.
2 Divide the dough in half, placing one half in the fridge until it's needed again in step 4. Using a rolling pin, roll out the other half of dough on a lightly floured surface into a 9x12-inch rectangle. Using a pizza cutter or sharp knife, cut the sheet of dough into nine 3x4-inch rectangles. Using a spatula, transfer the rectangles to the prepared baking sheet from step 1. 
3 In a small bowl, make a vegan 'egg wash' by whisking together maple syrup and non-dairy milk. Brush the 'egg wash' on each of the rectangles. Spoon 1 tablespoon of Strawberry Raspberry Preserves into the center of each rectangle, leaving a 1/2-inch of space around the edges.
4 Remove the other half of dough from the fridge and roll out and cut it the same way you did the first half, as directed in step 3. One at a time, place the second rectangle of dough on top of the nine partially assembled ones. Using a fork, press around the seams of the dough together, making sure they are sealed. Using the fork still, prick the tops of the rectangles in multiple spots, creating air holes, to allow steam to escape.
5 Refrigerate the baking sheet with the nine assembled pop tarts for 30 minutes, uncovered.
6 While the pop tarts are chilling, preheat the oven to 350 degrees F.
7 Bake the pop tarts for 25 to 30 minutes, or until lightly browned. Allow them to cool completely before icing. 
8 In a small bowl, whisk together the powdered sugar, non-dairy milk, and red food coloring. The icing should have a very thick, but still spreadable, consistency. If necessary, add a 1/2 teaspoon of milk at a time, until that consistency is reached. Spread a spoonful of icing over each pop tart, top with sprinkles, and allow to sit for at least 15 minutes so the icing can set. 
9 Enjoy right away or store in an airtight container at room temperature for 3 days.