I start by whisking the flour and salt together in a large bowl, then cutting in the cold butter until it looks like coarse pea-sized crumbs. Adding ice water a tablespoon at a time helps the dough come together without turning tough. I shape it into a disk, wrap it in plastic, and pop it in the fridge to chill for 30 minutes before rolling.
Once the dough has chilled, I roll it out on a lightly floured surface until it's about a quarter-inch thick. I trim the edges so they're neat, then cut it into even rectangles. This step determines how uniform your finished pop tarts look, so I take my time here.
I spoon a small amount of raspberry jam onto half of the rectangles, leaving a clean border around the edges. Too much filling can cause leaks in the oven, so I stick to about a tablespoon per pastry. Less really is more at this stage.
I brush the borders with egg wash, then place the second piece of dough on top of the filling. Using a fork, I press firmly around all four edges to seal everything in tightly. This crimping step is what keeps the raspberry filling from bubbling out while baking.
After poking a few small vent holes in the top with a fork, I brush the whole pastry with more egg wash and slide the tray into a 350°F oven. I bake them for 30 to 35 minutes, until they're a deep golden brown and smell absolutely incredible.
Once they're out of the oven, I let the pop tarts rest on the baking sheet for about ten minutes before moving them to a cooling rack. While they cool, I whisk together powdered sugar, milk, and vanilla for the glaze, then drizzle or spread it over the top and finish with sprinkles.