Preheat your oven to 350°F (175°C) and prepare an 8×8-inch baking pan by lining it with parchment paper.

Cream together the softened unsalted butter and powdered sugar until fluffy. Mix in the salt and optional vanilla extract, then gradually add all-purpose flour to create a soft dough.

Press the dough evenly into the lined pan. Bake for 20–22 minutes, or until the edges are lightly golden. Cool completely.

Melt soft caramel candies with heavy cream in a saucepan over low heat, stirring until smooth. Pour over the cooled shortbread and chill for 30 minutes.

Microwave chocolate chips in a bowl, heating in 30-second intervals until smooth. Pour over the chilled caramel layer.

Chill assembled bars in the refrigerator for 30–60 minutes until chocolate topping is set.

Slice into bars using a warm, sharp knife. Store in the fridge.