To make the crust:
1. Preheat oven to 325º
2. In a large bowl, combine the butter and sugars. Using mixer on medium speed, beat together until creamy. Add the vanilla and beat unti combined. Sift the flour into the butter mixture and beat on low speed until a smooth soft dough forms.
3. Spray a 9x13 inch baking pan lightly with non-stick spray. Press one-third of the dough evenly into the pan to form a botton crust. Wrap remaining dough in plastic wrap and chill in regrigerator.
4. Bake crust until firm and the edges are a pale golden brown approx 20 minutes. Transfer pan to a wire rack and let cool about 25 minutes.
To make the Filling:
1. While the bottom crust is baking and trhe remaining dough is chilling, make the caramel filling. Place the unwrapped caramels in a microwave safe bowl. Add the 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-seconds intervals, stirring after each interval until smooth.
2. Once the caramel is melted add in your ½ tsp vanilla and stir until combined.
3. Pour the caramel filling over the crust. If you are going to salt the caramel sprinkle it on caramel layer now.
4. Remove the remaining chilled dough from the refrigerator and crumble it evenly over the caramel.
5. Return the pan to the oven and bake until the filling is bubbly and the crumbles shortbread topping is firm and lightly golden, about 25-30 minutes.
6. Let cool before cutting into squares.
*Store airtight for up to 5 days.