Step 1

Preheat oven to 325°. Coat a 9×13 baking dish with nonstick spray. Set aside.

Step 2

In the bowl of your stand mixer fitted with the paddle attachment, mix the butter, granulated sugar, and powdered sugar together on medium speed for 2 minutes. Add the vanilla and mix until combined. Turn the mixer to low and add in the flour, mixing until a soft dough forms.

Step 3

Press one-third of the dough evenly into the bottom of the prepared pan. Wrap the remaining dough in plastic wrap and chill in refrigerator.

Step 4

Bake for 20 minutes, or until the edges are a pale golden brown. Transfer the pan to a wire rack and let cool about 15 minutes.

Step 5

While the bottom crust is baking and the remaining dough is chilling, make the caramel filling. Place the unwrapped caramels in a microwave-safe bowl. Add the milk or cream. Microwave on high for 1 minute. Remove from the microwave and stir until smooth. If caramels are not completely melted, microwave on high for 30-second intervals, stirring after each interval, until smooth.

Step 6

Once the caramel is melted add in your ½ teaspoon of vanilla and stir until combined.

Step 7

Pour the caramel filling over the cooled crust. If you are going to salt the caramel sprinkle it on caramel layer now.

Step 8

Remove the remaining chilled dough from the refrigerator and crumble it evenly over the caramel.

Step 9

Return the pan to the oven and bake until the filling is bubbly and the crumbled shortbread topping is firm and lightly golden, about 25 – 30 minutes.

Step 10

Let cool completely before cutting into squares.