In a large bowl combine flour, salt, and xanthan gum (if needed)

Grate butter on top of flour mixture. Combined the dry ingredients with the butter using your hands until fully incorporated.

Add vanilla and applesauce. Combined until it becomes crumbley.

Add water a tablespoon at a time, up to 6 tbsp, combining with your hands until it is a smooth ball of dough.

Wrap ball of dough in plastic wrap and refrigerate for at least 30 minutes.

Preheat the oven to 350°. Line baking sheet with parchment paper.

On lightly floured surface, roll the dough out to 1/8-1/4 inch thickness. Cut dough into 3x4 inch rectangles. Rework the dough and continue cutting out rectangles until all dough has been used. Reflour the surface regularly to prevent sticking.

Place 1 row of rectangles on the baking sheet. Spoon 1-2 tbsp of jam or filling of choice onto the center of each rectangle. Spread the filling out, but make sure it isn't too close to the edge of the rectangle.

Carefully brunch the edge of the pastry with milk using a pastry brush or your finger.

Top each rectangle with a second rectangle of dough. Using your fingers or a fork, lightly press all the way around to seal the edges. With a sharp knife or fork, poke holes in the top of the pastry.

Bake the pastries until golden brown, 25-30 minutes.

Remove from oven and allow to cool completely.

Top with a glaze by combining 1/2 cup powdered sugar and 1-2 tbsp of milk in a bowl and then spreading the glaze on top.