• Preheat your oven to 350°F. Line a large rimmed baking sheet with unbleached parchment paper and set it aside.

Prepare the crust.

• In a large bowl, place the flour, xanthan gum, cornstarch, salt, and granulated sugar, and whisk to combine well.
• Create a well in the center of the dry ingredients and add the melted butter, vanilla, beaten egg, and 1/4 cup milk and mix to combine. The dough will be thick.
• Knead the dough with your hands until it’s smooth, adding more milk by the half-teaspoonful as necessary to bring the dough together.
• Divide the dough into two equal parts and work with one at a time, covering the other with plastic wrap or a towel to prevent it from drying out.
• Place the first piece of dough on a lightly floured surface and dust lightly with more flour to prevent it from sticking. Roll out the dough about 1/4-inch thick, moving the dough frequently and sprinkling it with more flour as necessary.
• Slice it into rectangles approximately 3-inches x 4-inches. Reroll each rectangle a bit more until it’s a bit less than 1/4-inch thick.
• Gather and reroll scraps, and repeat with the other half of the dough. There should be at least 24 rectangles in total. If you have fewer, try for at least an even number of rectangles because you’ll be pairing them.

Prepare filling/assemble pastries.

• Placing all the filling ingredients in a small bowl and mixing them to combine well.
• Place about 1 tablespoon of filling in the center of of half of the rectangles of dough and spread it into an even layer, leaving about a 1/2-inch border clean on all sides.
• Cover the filling on each rectangle with a matching rectangle, and press all around the clean edge to seal. Trim any unmatched or jagged edges.
• Place the pastries about 2-inches apart from one another on the prepared baking sheet. Dock the pastries by piercing them all over the top with a toothpick or the tines of a fork.

Bake the pastries.

• Place the baking sheet in the center of the preheated oven and bake until the pastries are very lightly golden brown on the edges and set in the center, about 8 minutes.
• Remove from the oven and allow the pastries to cool completely.

Make the glaze/glaze the pastries.

• In a small bowl, place the confectioners’ sugar and ground cinnamon, and mix to combine well. Add the 2 teaspoonful of water and mix until combined into a thick paste.
• Add more water by the half-teaspoonful as necessary to create a thickly pourable glaze.
• Spread the glaze generously on top of each cooled pastry. Allow to set completely at room temperature.