First, follow my pie crust dough recipe to make enough dough for 1 9-inch pie crust, or you can use a storebought pie crust of course. If using homemade, chill the dough for an hour before using it.
Preheat the oven to 375 F/190 C. Use a ruler and cut the dough into equal rectangle shapes about 3x4 inches. You can make them smaller or even larger if you want. Place the dough on a sheet pan lined with parchment paper or a silicone mat.
Now poke holes in half of the pieces of dough, these will be used for the tops. Then spoon 1.5 to 2 tablespoons of jelly or jam in the middle and spread it out so it is a small inner rectangle. It may help to heat up the jelly a little bit, it spreads easier this way.
Place the top piece of dough over the jelly and crimp the edges with a fork. You can also use a basic egg wash and brush the edges and the tops if you like. Sometimes it helps create a better seal around the edges.
Bake the pan on the middle rack for 18 to 25 minutes until golden brown. Once baked, allow them to cool completely. It is normal to have a bit of leakage out the sides. You can trim away the leakage if desired.
Make the glaze by mixing together the powdered sugar, milk, and vanilla extract. Add more sugar or milk to get the consistency you desire. I like it nice and thick. Spread the glaze on the tops of the pop tarts and then finish them off with sprinkles.
Allow the glaze to set and then serve. Enjoy! Store them in an airtight container or zip lock bag at room temperature for 2 to 3 days. Or in the fridge for about a week. You may also freeze them.