In a large bowl, whisk together the flour, sugar, and salt. Add butter and use a pastry cutter, fork or hands to mix until it resembles coarse crumbs.

Add the egg and milk, and mix until the dough comes together. .

Divide the dough in half, shape each half into a 3" x 5" rectangle, wrap in plastic, and refrigerate for 1 hour.

Combine all the ingredients except the egg in a saucepan set over medium heat.

Cook until the mixture starts to thicken, about 5 minutes. Transfer to a bowl. and cool to room temperature.

Preheat the oven to 350°F. Lightly grease a baking sheet, or line it with parchment paper.

After 1 hour, remove the dough from the refrigerator. Allow to sit for about 10 minutes before rolling out.

Place one piece of dough on a lightly floured work surface, and roll it into a 9" x 12" rectangle. Trim the edges to make them straight. Cut out nine 3" x 4" rectangles. Repeat with the remaining dough. (You can do whatever size/shape you prefer, just make sure you have an even number for tops and bottoms!)

Divide the filling among nine of the rectangles, using a heaping tablespoon for each. Brush some beaten egg along the edges.

Cut a vent into the remaining rectangles, using a small, sharp knife, or a decorative cutter if you have one.

Top the filled rectangles with the vented rectangles. Press along the edges with the tines of a fork or a crimper to seal.

Brush the tops of the pies with beaten egg, and sprinkle with sparkling sugar. Transfer to the baking sheet.

Bake the pies for 28 to 33 minutes, until they're a light golden brown. Remove them from the oven, and cool on the pan.