Add sugar, softened butter, and vanilla extract to the bowl of a stand mixer. Beat using the paddle attachment until combined and fluffy.

If your flour is not pre-sifted, sift it using a fine mesh sieve. Then whisk together flour, and salt in a mixing bowl and add to the beaten butter mixture. Mix until a dough forms.

Scrape the dough out of the bowl onto a piece of plastic wrap, shape into a disk or a rectangle. Refrigerate for at least 30 minutes to 1 hour.

Now use the heart-shaped Linzer cookie cutter insert to create the heart cutout in the middle of each cookie. Place the cookies and heart cutouts in a container in layers with parchment paper in between and freeze while the oven is preheating.

Preheat the oven to 350°F.

In the meantime, unwrap the hard candies, place them inside a plastic bag, wrap the bag with a towel and crush the candies with a rolling pin. Place the crushed candies into a small bowl and set aside.

When the oven is ready, place the cutout cookies on a parchment lined baking sheet 1 to 2 inches apart. Sprinkle granulated sugar over the top of cookies generously and bake for 10 - 11 minutes.

Remove the baking sheet from the oven and use a ¼ teaspoon to add crushed candied inside the heart-shaped cutouts, fill it all the way to the top. Place the baking sheet back into the oven, and bake for another 3 minutes until the candies are completely melted.

Remove the baking sheet from the oven and set it on a wire rack. Allow the cookies to cool on the baking sheet until the melted candy hardens, about 5 - 10 minutes, before moving the cookies to a wire rack to cool completely.

To bake the bite size heart cutouts, place them on a parchment lined baking sheet an inch apart. Sprinkle granulated sugar over the top of cookies generously and bake for 8 minutes.