Preheat oven to 325°F. In stand mixer with paddle attachment, beat together butter, icing sugar, salt and vanilla until light and fluffy, at least 3 minutes.

Add flour to mixture and mix until just combined. A ball of dough will begin to form.

Remove dough from stand mixer and knead with hands until full ball forms, about 1 minute. Wrap in plastic wrap and refrigerate for at least 30 minutes to harden.

Roll out dough with rolling pin, adding extra flour to rolling surface and rolling pin if dough sticks. Roll to ¼ inch thickness.

Using 3-inch circle cookie cutter, cut out circle shapes, rerolling and cutting scraps.

Using 1½-inch Christmas tree cookie cutter, cut out shape in center of half the circle cookies.

Arrange whole and cutout cookies on parchment-lined baking sheets.

Bake on top and bottom racks, rotating and switching pans halfway through, until edges are light golden, about 15-20 minutes.

Remove cookies from oven and let cool completely.

Spread jam over bottom of each whole cookie. Dust icing sugar over cutout cookies. Place cutout cookies on jam-filled cookies, sugar side up.