Plan ahead! This pastry dough needs some time to chill in the refrigerator. After making the dough, refrigerate at least 2 hours or up to 5 days. (Or freeze for up to 3 months.)Make the pastry dough. I use a food processor to make this dough, but you can use a large bowl and make this by hand too. Mix together the flour and salt. Add the cold butter and vegetable shortening then pulse in the food processor until small, pea-sized crumbles form. Alternatively, use a pastry cutter or two forks and cut by hand. Slowly drizzle in ice water 1 Tbl at a time and gently stir or pulse to combine. Stop adding water when the dough begins to clump together. Roll the dough out on a floured workbench and form two 1-inch thick discs. Wrap tightly in plastic wrap and refrigerate at least two hours or up to 5 days.
Roll. On baking day, let the pastry dough sit out at room temperature for 10 minutes before rolling out into a a floured surface. The dough should be rolled into an 1/8-inch thick rectangle measuring 9x12 inches. Trim as needed and then using a ruler, cut rectangles 3x4 inches in size. From each disc of dough you should be able to get 9 rectangles. Place the rectangles onto baking sheets lined with parchment paper and place them back in the refrigerator to firm up.
Make the filling. While the pastry dough is chilling again, make the cinnamon brown sugar filling. In a small bowl, use a fork to mix together the brown sugar, cinnamon, and flour. Make a quick egg wash by beating together 1 egg and 2 tsp milk in a separate bowl.
Assemble. Working quickly, remove the dough rectangles from the refrigerator and lightly brush each of them with egg wash. Use a heaping tablespoonful of cinnamon brown sugar filling for each of 9 pop tart bottoms, spreading it to within 1/4-inch of the edge. Carefully place the top crust over the filling, but this time egg wash side down. This will help to seal in the filling during the baking process. Use a fork to crimp the edges. Repeat with remaining filling and dough rectangles until you have 9 pop tarts assembled. Lightly brush the tops of the pop tarts with egg wash. If the dough has warmed up too much, return the uncooked pop tarts to the refrigerator to chill, otherwise proceed to the baking step next.
Bake. Bake for 22-28 minutes or until golden brown on top, rotating the pan halfway through the baking time. Remove from the oven and cool completely.
Glaze. When the pop tarts are completely cooled, make this quick glaze. Whisk together powdered sugar, cinnamon, vanilla, and start with 1 Tbl milk. This mixture will be very thick, but should still be spreadable. Carefully spoon 1/2 tsp over the top of the baked pop tart and spread to the crimped edge. Allow glaze to set up, about 1 hour.
Makes 9 3x4 pop tart pastries.
Adapted from Sally's Baking Addiction
