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

Continuing with the stand mixer, add flour to the mixture until just combined. A ball of dough will begin to form.

Remove dough from stand mixer, and knead with your hands until a full ball forms, about 1 minute. Wrap in plastic wrap, and place in fridge for at least 30 minutes.

On a floured surface, roll out dough with a rolling pin to ¼ inch thickness. Use extra flour if dough begins to stick.

Using a 3 inch circle cookie cutter, cut out circle shapes, rerolling and cutting scraps. Using a 1 ½ inch heart cookie cutter, cut out shape in center of half of the circle cookies.

Arrange whole and cutout cookies on parchment-lined baking sheet. Bake on top and bottom racks, rotating and switching pans halfway through, until edges are light golden, about 15-20 minutes.

Remove cookies from the oven and let them cool. Dust icing sugar over cutout cookies.

Spread jam over bottom of each whole cookie. Place one cutout cookie on top of each whole cookie with jam filling, sugar side up.