Preheat oven to 325 degrees. Line a9 x13 pan with parchment paper or aluminum foil. Lightly spray with cooking spray.
In a large mixing bowl cream together butter, sugar, and powdered sugar. Add vanilla and beat until combined. Mix in the flour and combine until it forms a soft dough.
Press half of the dough in the bottom of a 9×13 dish and place the other half of the dough into the refrigerator. Bake in preheated oven for 15 minutes.
Remove the pan from the oven and melt the caramels, heavy cream and ½ tsp vanilla in the microwave for 1 minute. Stir together until smooth. Pour evenly over the hot crust. Lightly sprinkle the coarse sea salt over the crust. I didn’t end up using the entire T, just lightly sprinkle evenly on top. You don’t want them too salty.
Take the remaining dough out of the refrigerator and crumble over the top of the caramel. Return the pan to the oven and bake for 25-30 minutes until filling is bubbly and the top is firm. Let them cool completely before cutting.
