In a large mixing bowl, use a hand-held mixer to beat together the butter and the cream cheese until light and fluffy.
Add the flour and salt. Beat into the butter mixture.
Divide the cookie dough into four equal portions and flatten each portion to 1/2 inch thick. Wrap in plastic wrap and refrigerate for 2 hours.
When ready to assemble and bake, preheat oven to 375 degrees and line a baking sheet with parchment paper or a silicone baking mat.
Remove one portion of the dough from the fridge and roll to 1/8th of an inch thick on a lightly floured surface. The dough is sticky so be sure to flour your rolling pin too.
Cut the rolled dough into 2 inch squares. Remove scrap dough to the side to use later once the currant batch is baking.
Place one tablespoon of the apricot preserves into the center of each square of dough. Gently fold up two opposite corners so that the slightly overlap. Push down just slightly with your finger to seal the dough together.
Transfer the cookies to the baking sheet, leaving at least 2 inches of space between each cookie.
Sprinkle each cookie with a little sanding sugar and bake for 12 minutes or until the edges are a light golden brown.
Remove from oven and allow cookies to cool on the baking sheet for 5 minutes. Then, remove the cookies from the baking sheet to a wire cooling rack to finish cooling.
Repeat steps 5 to 10 with the remaining 3 portions of dough in your fridge.