
Whisk together the flour, sugar, and salt. Add in the cold cubed butter and cut in using a pastry cutter or forks until it forms pea-sized crumbles. Whisk together the egg and milk and add to the dough, mixing until it clumps together.
Roll out the dough on a floured surface. Form into a ball, divide in half, shape into discs, wrap in plastic wrap, and refrigerate for at least 2 hours.
Roll out the dough and cut into rectangles, place on a baking sheet, and refrigerate while making the filling.
Mix brown sugar, cinnamon, and flour. Brush one sheet of rectangles with egg wash, add filling, top with the second rectangle, seal and poke holes.
Refrigerate the filled pop-tarts for at least 20 minutes.
Preheat oven to 350°F, brush with egg wash and bake for 22-26 minutes until golden brown.
Whisk glaze ingredients together until spreadable. Glaze pop-tarts once cooled.
Store in an airtight container at room temperature for 3 days or in the fridge for a week.