Line two baking sheets with parchment paper.
Beat the butter and sugar in a mixing bowl until light and fluffy for about 3-5 minutes using the paddle attachment. Add the egg yolk and vanilla and beat for 1 more minute. Gradually add in the flour a ½ cup at a time, and then the salt. Mix gently until just combined.
Divide the dough in half and form into a disc wrapped in plastic wrap and refrigerate for 1 hour.
Lightly flour a surface, and roll out one disc until ¼” thick. Using a round cookie cutter, cut out cookies and place on parchment paper ½” apart. Roll out the second dough to ¼” thick, cut out the dough using a cookie cutter, and using a small shape cookie cutter to cut out the centers. Place cookies on the second baking sheet and place both sheets in refrigerator for one hour.
Bake cookies for 8 minutes at 350°F until the edges are beginning to turn golden. Place baking sheets on wire rack and allow to cool in the pan for 5 minutes, before transferring them directly onto the rack until fully cooled.
Once cool, add 1 teaspoon orange marmalade to the bottom cookies, and evenly spread out.
Place the cut out cookies over top.
Place the chocolate in a heatproof bowl, then place the bowl over a saucepan of simmering water. Continue to stir until melted, smooth and glossy. Dip ½ of each cookie in the chocolate and place on a baking sheet lined with parchment paper. Place cookies in the refrigerator for a few minutes until chocolate hardens.