Cream together butter, sugar and salt until mixture is light and smooth.
Add in whole eggs and vanilla essence and mix until well combined.
Gradually add in flour until a dough ball is formed. Rest dough in the fridge for approx. 1 hour.
Roll the dough out into a thin layer. Cut out various shapes as desired using cookie cutters, with the center removed. Repeat until all of the dough is used.
Using a food processor, blend the hard candies until they become small and fine pieces.
Fill the center of the cookies with the blended hard candies.
Bake at 140°C for approx. 10 – 15 minutes. Monitor the candies throughout the whole baking process. Once the candies have melted, remove cookie tray from oven and add another layer of candies. Continue to bake until candy has melted and cookies are nicely baked.