Preheat the oven to 350 degrees F.
If using raw pistachios, put the nuts on a baking sheet and toast, shaking the sheet after a few minutes, until the pistachios start to look shiny, about 8 minutes. Allow to cool completely.
Put the pistachios in a food processor and pulse until you have a fine meal. Be careful to not over-process otherwise you will create a paste. Combine the flour, baking powder, salt and ground pistachios in a medium bowl and mix well. Set aside.
In a stand mixer, cream the butter until it lightens in color, about 3 minutes. Add the sugar and mix until light and fluffy, another 3 minutes. Add the egg and vanilla seeds and beat until fully incorporated, 2 minutes. Scrape the sides of the mixing bowl and mix for another minute. Add the flour mixture and mix on low speed until the dough comes together. Scrape down the sides of the bowl and beat for an additional 10 seconds. Divide the dough into three disks. Wrap the dough in plastic wrap and refrigerate for 1 hour.
Dust a workspace with flour and roll out one dough disk to 1/8-inch thickness. Using holiday-shaped cookie cutters or a round cutter, cut out cookies and transfer to a baking sheet. Space the cookies 1 inch apart. If using different shaped cutters, be sure to make an even amount of each shape. Save all the scraps. Repeat the process with the other two disks of dough. Take the remaining scraps and gently gather them together. Repeat the process once more. Depending on the size of your cookie cutters, there should be about 72 cutouts. Using a small round cutter, cut out holes in the center of half the cutouts.
Bake until the edges begin to brown slightly, 9 to 11 minutes. Allow to cool on the baking sheets for 3 minutes before carefully transferring to a rack to cool completely.
Take a spoon and stir the sour cherry jam to loosen it up. Spread 1/2 teaspoon of jam onto the cookies without the holes, going as close to the edges without going over. Sprinkle the cookies with the cutout holes generously with confectioners' sugar. Top each jam-covered cookie with a sugar-sprinkled cookie to create a sandwich. Store in an airtight container up to 3 days.