• Preheat the oven to 325°. Lightly spray the bottom of a 9" X 13" baking pan with nonstick spray.

Making the Crust

• Mix the butter, granulated sugar, and powdered sugar together in a bowl fitted with the paddle attachment. Mix at medium speed for 2 minutes until creamy. Add the vanilla and mix until combined.
• Turn the mixer to low and gradually add the flour, mixing until a soft dough forms. Don't overmix.
• Press ⅔ of dough into prepared pan smoothing evenly over the bottom of the pan and coming up just a bit on the sides. This prevents the caramel from oozing over.
• Wrap the remaining dough in plastic wrap and chill in fridge while crust is cooking.
• Bake for 20 minutes or just until edges are pale golden brown. Remove from over and place on a wire cooking rack for about 15 minutes.

Making the Caramel Filling

• While the crust is baking, place the caramels in a microwave-safe bowl and add the cream. Microwave on high for 1 minute. Remove and stir with a whisk until smooth. If caramel is not completely melted, microwave on high for 30 second intervals stirring until smooth.
• After the caramel is melted, add the ½ t of vanilla and stir until combined.
• Pour the caramel over the crust. Sprinkle lightly with sea salt, if desired.
• Crumble and sprinkle the remaining chilled dough evenly over the caramel.
• Bake for 25 minutes or until the filling is bubbly and the crumbled shortbread in firm and light golden brown.
• Let cool completely before cutting into squares. Or eat warm but not hot!