Using a food processor, add the flour, salt and sugar to the bowl. Pulse several times until well mixed. (Note: You can also use a large bowl and a pastry cutter to make this dough.)

Cut the butter into ½” cubes and add to the dry ingredients. Pulse 10-12 times, or until mixture resembles a coarse meal.

Add water and pulse several times, or until mixture comes together.

Turn dough out onto floured countertop and divide into two equal pieces. Shape each piece into a disk and wrap with plastic wrap. Place both disks in the refrigerator for at least 2 hours, or overnight.

Line a baking sheet with parchment paper; set aside.

On a well-floured countertop, roll out 1 disk into a 6” x 14” rectangle. Using a pastry wheel (to create fluted edges), cut out (4) 6”x3½” rectangles of dough.

Spread 1 Tbsp of jam evenly across the tops of 2 pieces of dough, leaving a ½” border around the outside of the dough.

Whisk the egg together with 1 tsp of water. Brush the edges of the dough with the egg mixture. (Note: Save the remaining egg mixture as it will be brushed on top of the pastries later.)

Place the remaining 2 pieces of dough on top of the jam-filled pieces; press dough together around edges to seal. Place pastries on prepared baking sheet. Repeat with remaining disk of dough.

Place baking sheet in refrigerator for 30 minutes.

Preheat oven to 350°F.

Brush the tops of the pastries lightly with egg mixture. (Note: Not all of the egg mixture will be used; discard any remaining mixture.)

Bake pastries for 25-28 minutes, or until golden brown in color. Let cool on pan for 10 minutes before transferring to a cooling rack until fully cooled.

In a small bowl, whisk together the powdered sugar and milk. Using an offset spatula, spread the icing evenly across top of the pasties. Decorate pastries with sprinkles or sanding sugar. Let icing harden completely before serving.