In the bowl of a mixer, beat the butter and sugar until smooth, about 2 minutes.
Add the eggs one at a time, beating well after each addition.
Add the vanilla and salt, then slowly mix in the flour until thoroughly combined.
Remove the dough from the bowl. Place the dough on a large piece of plastic wrap and shape it into a disc. Wrap the plastic wrap around the dough and chill for at least 1 hour, or up to 1 day before you plan to bake your cookies.
Preheat the oven to 350 degrees. Line a sheet pan with parchment paper or a nonstick baking mat.
Divide the dough in half. Re-wrap one half of the dough and place it in the fridge. Roll the remaining dough into a 1/2 inch thick rectangle.
Using a 4 inch star shaped cookie cutter, cut out as many shapes as you can from the dough. Place the stars 1 inch apart on the cookie sheet, and use a 2 inch star cookie cutter to cut out your windows.
Re-roll the dough and repeat the process until you've filled your first baking sheet.
Gently press sparkling sugar into the tops of the cookies.
Place the pan of cookies in the fridge and chill for 20 minutes.
Remove the cookies from the refrigerator. Fill each cookie 2/3 of the way full of crushed candy, using a toothpick to nudge the candy into small crevices.
Bake for 10-12 minutes or until cookies are light golden brown and the candy has melted. Cool completely.
Repeat the same process with the other half of the dough that you previously put in the refrigerator.
Store covered in a single layer for up to 2 days.