Brush with egg wash: Remove one baking sheet of chilled rectangles from the refrigerator. Lightly brush each rectangle with egg wash.
Fill with preserves: Spoon about 1 tablespoon of strawberry preserves into the center of half the rectangles, leaving a border around the edges.
Strawberry preserves
Top with second rectangle of dough: Top each with a second rectangle of dough. Press the edges together gently, then use a fork to crimp and seal all sides.
Brush tops with egg wash: Lightly brush the tops with egg wash. Using a toothpick or skewer, poke 6-8 small holes in the tops to allow steam to escape.
Chill and repeat: Return the assembled pop tarts to the refrigerator while you repeat with the remaining dough. You should have about 8–10 pop tarts total.
Bake: Preheat the oven to 400°F. Bake for 15-18 minutes Start Timer, or until the tops are lightly golden brown. Allow the pop tarts to cool completely before glazing.
Make the glaze: Whisk together the powdered sugar, milk, corn syrup, vanilla, and salt until smooth.
1 cup powdered sugar, 1-2 Tbsp. milk, 2 tsp. light corn syrup, 1/2 tsp. vanilla extract, Pinch of salt
Glaze pop tarts: Spread glaze over cooled pop tarts and decorate with sprinkles.
Rainbow jimmies or nonpareils
Let cool and enjoy: Allow the glaze to set before serving.