Preheat the oven:
Set your oven to 375°F (190°C).
Prepare the crusts:
On a large cutting board, roll two of the pie crusts together. Using a pastry wheel or sharp knife, trim the combined crusts into a 12×16-inch rectangle (or a size that fits your sheet pan). Carefully roll the crust up and transfer it to a sheet pan that’s been sprayed with non-stick cooking spray.
Spread the filling:
Spread the strawberry preserves over the center of the crust, leaving a 1-inch border around the edges.
Top with the second crust:
Roll the other two pie crusts together and trim to match the size of the first. Place it on top of the strawberry jam layer.
Seal the edges:
Use your fingers to pinch the edges of the two crusts together. Then, use a fork to crimp the edges to ensure the jam is sealed inside.
Vent the crust:
Poke small holes all over the top crust using a toothpick to allow steam to escape while baking.
Brush and bake:
Brush the top and edges of the pop tart with softened butter. Bake for 25 minutes or until the crust is golden brown, rotating the pan halfway through baking. Keep an eye on the edges to prevent any jam from seeping out. If it does, you can place a larger pan underneath to catch drips or scoop the jam back into place.
Cool and prepare icing:
Remove the pop tart from the oven and let it cool. In the meantime, mix powdered sugar and milk in a bowl until smooth and spreadable.
Ice and decorate:
Spread the icing over the center of the pop tart, leaving the crimped edges bare. Immediately add sprinkles on top.
Serve:
Slice the giant pop tart into pieces and enjoy!