Preheat your oven to 350°F (175°C) and spray a baking pan with non-stick cooking spray.

In a mixing bowl, combine the yellow butter cake mix, softened butter, and egg until crumbly and well combined.

Press two-thirds of the mixture evenly into the prepared baking pan and bake for 13-15 minutes until pale golden brown.

Melt the caramel bits with heavy cream in a microwave-safe bowl until smooth, then stir in vanilla extract.

Pour the melted caramel over the baked shortbread base and sprinkle with kosher salt if desired. Crumble the remaining dough on top.

Bake for an additional 15 minutes, then cool completely before slicing into squares.

Once cooled, slice into 12 squares and enjoy or serve at your next gathering.