In a medium bowl, combine flour and salt. Add butter and work into flour with your fingers until butter is in pea-sized chunks. Stir in about ¼ cup ice water to form a shaggy ball of dough. If still too dry, add 1-2 tablespoons more ice water. Flatten into a disk, wrap in plastic wrap, and refrigerate 1 hour.

Make the filling. In a medium skillet, boil apple juice until reduced by ¾, about 10 minutes. Add diced apples and spice. Cook over medium heat until apples are softened, about 5 minutes. In a small bowl, whisk together cornstarch and 2 tablespoons cold water. Stir cornstarch into apple mixture and cook until thickened. Remove from heat.

Preheat oven to 375ºF. Roll out dough 1/8-inch thick. Using a 2 ½ - 3” round cookie cutter, cut out rounds of dough. Place half the dough rounds on a parchment-lined cookie sheet. Press a lollipop or popsicle stick into the center of each dough round 1 inch from the edge.

Place a heaping teaspoonful of the apple mixture in the center of each dough round. In a small bowl, beat egg white with 1 teaspoon water. Brush the edges of the dough rounds with the egg white and place a second round of dough on top of the apple filling. Use the tines of a fork to seal the edges of the pops.

In a small bowl, beat the egg yolk with 1 teaspoon water. Brush the tops of the pops with egg yolk and sprinkle with sugar. Bake 20-25 minutes or until golden brown. Let cool on the baking sheet.