In a large bowl, add the flour, salt, and sugar. Stir together with a fork.
Cut vegan shortening into tablespoon size cubes and then using a fork combine together until crumbly.
Pour in milk and vanilla.
Stir until combined.
Use hands to form a dough.
Lay a piece of parchment paper down and sprinkle with flour. Lay dough down and sprinkle with a touch of flour on top.
Roll out dough into an 18x24 inch rectangle. Tip: If you don't have a lot of counter space, split dough in half and roll out each piece into a 9x12 inch rectangle. Cut the dough vertically from the longest side every 3 inches. You should end up with 8 strips of dough. *If doing the 2 9x12 rectangles, cut each piece into 4 strips.
Lightly brush the dough with vegan milk.
Preheat oven to 425 degrees.
Once blueberry filling has cooled completely, fill the lower 4 inches of dough with mixture, about 1-2 tablespoons. Leave 1/2 inch between each side.
Fold the top half of the dough over on top of the bottom.
Firmly press them together trying not to leave any air pockets.
Use a fork and press along all the edges.
Place on a baking sheet lined with parchment paper.
Brush the tops with more vegan milk.
Bake for 20-30 minutes or until lightly golden brown on top and around edges.
Place on a cooling rack and let cool completely.
Make the icing by adding powdered sugar to a bowl and whisk in a teaspoon of water at a time until slightly runny.
Add in the vanilla and whisk again.
Dip the tops of the pop tarts into the icing or drizzle on top.
Add sprinkles or chopped cereal on top if desired.
Serve or store in an air tight container - room temperature for 1-2 or 7 days in the fridge. Can freeze for up to 6 months.