In a large bowl, combine the flour, salt, and xanthan gum.

With a cheese grater, shred the butter on top of the flour mixture. Using a pastry cutter or your hands, combine the flour mixture and the shredded butter until thoroughly incorporated.

Add the vanilla and applesauce to the flour, stir to combine. Add 4-6 tablespoons of the water and combine by hand until a smooth dough ball can be formed. Be careful not to overmix the dough, or it will begin to crumble and break.

Form the dough into a ball and wrap it tightly in plastic wrap. Refrigerate for at least 30 minutes.

Preheat the oven to 350F, and line a baking sheet with parchment paper.

On a lightly floured surface, roll out the dough to ⅛- to ¼-inch thickness. Cut the dough into sixteen 3 x 4-inch rectangles. You’ll need to rework the dough and roll it out a few times, making sure to re-flour the surface.

Place one row of rectangles on the baking sheet. Spoon about 1 tablespoon of strawberry filling onto the center of each rectangle, making sure the filling doesn’t get too close to the edges. Carefully, with a pastry brush or your finger, brush milk onto the edges of each rectangle.

Top each rectangle with a second piece of the dough. Using your fingers press down the edges. Then, with a fork, lightly press down to seal all the edges of the dough. With a sharp knife, cut 3 or 4 small slits in the top of each pop tart.

Bake the pastries for about 25 to 30 minutes or until golden brown.

Remove from the oven, and allow them to cool completely.

To make the glaze, combine the sugar and milk in a small bowl. Spread over the cooled pop tarts and enjoy.