Apple-Cinnamon Pop Tarts

Whisk the flour, sugar, cinnamon, and salt in a large bowl until combined.

Add the butter and toss with your fingers until well coated in the flour mixture. Using a pastry blender or your fingers, cut or rub the butter into the dry ingredients until reduced to pea-size pieces.

Whisk the egg yolks and milk in a small bowl until combined.

Add the egg-milk mixture to the flour mixture and mix with your hands until large clumps form. Turn the mixture out onto a work surface and knead briefly, smearing the butter into the dough with the heel of your palm until the dough completely comes together, about 1 minute.Divide the dough into 2 equal portions and shape into 2 (6-by-5-inch) rectangles. Wrap tightly in plastic wrap and refrigerate for at least 1 hour. Meanwhile, make the filling.For the apple-cinnamon filling:Using a vegetable peeler or paring knife, peel the apples and discard the peel. Core the apples, then cut them into 1/4-inch-thick slices and again into 1/4-inch pieces.

Combine all the ingredients in a medium frying pan over medium heat. Cook, stirring, until the sugar has dissolved and the apple juices begin to release, about 5 minutes. Continue cooking until the apples just begin to soften, about 3 minutes more.

Heat the oven to 375°F. Line a baking sheet with parchment paper; set aside.Lightly dust a work surface with flour and roll 1 dough portion out into a rough 12-by-10-inch rectangle, rotating the dough and reflouring the surface and rolling pin often to prevent the dough from sticking. Using a pizza cutter or sharp knife, trim the dough to a 10-1/2-by-9-inch rectangle.

Cut that into 6 equal rectangles (each about 3 1/2 inches wide by 4 1/2 inches tall). Using a flat spatula, transfer the rectangles to the prepared baking sheet, leaving about 2 inches of space between each.

Place the baking sheet in the refrigerator.

Whisk the egg and water in a small bowl until evenly combined; set aside.

Roll out the second dough portion to the same dimensions as the first, trim, and cut into 6 rectangles. Using a fork, prick the dough all over.

Transfer 2 tablespoons of the cooled apple juices to a medium bowl and set aside for the glaze; set the remaining juices aside.

Remove the baking sheet from the refrigerator and brush a thin coating of the egg wash over each dough rectangle. Spoon about 1 heaping tablespoon of the apple filling onto each rectangle and spread it into an even layer, leaving a 3/4-inch border. Top each rectangle with 1 1/2 teaspoons of the remaining apple juices.

Place the pricked rectangles on top of the apple-covered rectangles. Press on the edges to adhere, and push down gently on the filling to slightly flatten. Using a fork dipped in flour, crimp the edges of the tarts.

Bake until golden brown, about 23 to 25 minutes.

Place all the ingredients in a small bowl and whisk until evenly combined. (You may need to add more milk by the 1/2 teaspoon if the glaze is too thick.)Set the wire rack with the tarts on it over a baking sheet. Using a spoon, drizzle about 1 tablespoon of the glaze over each pastry.

Let set before eating, about 15 minutes.