Preheat the oven to 400 degrees F. Line a baking sheet with parchment.
Spread one package of pie crusts out flat and cut out ten 3-inch squares. (If you're short a square or two, roll out the scraps and cut out more squares.) Spread each square with a healthy blob of White Chocolate Pistachio Butter. Using a spoon, make a divot in the center of the pistachio butter, then fill each divot with about a teaspoon of raspberry jam. Beat the egg with a splash of water and brush the edges of the crusts with egg wash.
Spread out the second package of pie crusts and cut out another ten 3-inch squares. Place these squares on top of the first and crimp the edges with a fork (seal them well!).
Poke the tops of the pocket pastries a few times with a fork and bake until slightly browned, 20 to 25 minutes. Let cool.
Press the remaining 1/4 cup jam through a strainer to remove the seeds. Gradually whisk the confectioners' sugar into the strained jam until you reach the desired consistency.
Spread the glaze on the cooled tarts, top with sprinkles and enjoy!
White Chocolate Pistachio Butter:
In a food processor, combine the pistachios, white chocolate chips, granulated sugar, salt, almond extract and vanilla. Process until very creamy and spreadable, stopping occasionally to scrape the sides of the bowl, about 10 minutes.