Preheat the oven to 400°. Line a baking sheet with parchment paper.

MAKE THE HAND PIES: In the bowl of a food processor, combine the flour with the salt and sugar. Add the cubed butter and pulse until the butter is the size of peas, about 2 minutes.

Gradually add the water through the top spout, and pulse just until the dough comes together. Remove the dough and wrap it in plastic. Chill in the refrigerator for at least 20 minutes.

Roll out the chilled dough on a lightly floured surface to ¼-inch thickness. Cut into 2-by-3-inch rectangles.

Place 2 tablespoons of jam in the center of half the rectangles. Dip your finger into cool water and run it around the edges of the dough. Place the remaining rectangles on top of the jam-covered ones, and press the edges with a fork to seal. Use a knife to cut a tiny vent into the center of the top piece of dough.

Place the pies on the prepared baking sheet and bake until golden brown, 10 to 13 minutes. Cool completely.

MAKE THE FROSTING: In a small bowl, whisk the confectioners’ sugar with the cream and vanilla. If the frosting is too thick, add more cream 1 tablespoon at a time until it is easily spreadable.

Frost each hand pie with about 1 tablespoon of frosting, and top with sprinkles, if desired.