Preheat oven to 325°F (163°C) and line a 9x13 inch baking pan with parchment paper.
Cream the butter and granulated sugar in a large bowl until light and fluffy.
Mix in the powdered sugar and vanilla extract.
Add the flour gradually on low speed until a soft dough forms.
Press one-third of the dough evenly into the bottom of the prepared pan.
Bake the crust for 15 minutes or until slightly firm.
Melt caramel candies and heavy cream in a saucepan over low heat, stirring until smooth.
Pour the caramel over the warm crust and sprinkle with fleur de sel.
Crumble the remaining dough evenly over the caramel layer.
Bake for 25 to 30 minutes until the topping is golden brown.
Allow the bars to cool completely at room temperature before chilling and slicing.