Grease an 8x8 baking pan with cooking spray. Then line with parchment paper, making sure the parchment paper goes up the sides of the pan so you can easily remove the bars. Spray the parchment paper again lightly.
Cream together the butter, vanilla and sugar, for about 3 minutes, until ultra light and fluffy then slowly mix in the flour until combined. It will be a little crumbly, but that's ok.
Press the dough into your parchment paper lined baking dish.
Use a fork to poke holes all over the surface of the dough. This will prevent the dough from doming while it bakes, helping to make sure you have one flat and even layer for the base.
Bake for about 25 minutes or just until it starts to show a hint of being golden brown.
When done, lift the parchment paper & cookie layer out of the baking dish and let everything cool on wire racks while you make the caramel layer.
To make the caramel layer:
Heat a medium saucepan over medium heat and start whisking everything but the vanilla extract together.
Keep whisking and be patient while the caramel mixture starts to come to a slow boil.
Turn down the heat to a simmer and continue to cook, whisking the entire time. I stirred this for about 20 minutes until it was visibly thickened and had darkened to a perfect caramel color. The temperature should be between 220-225 degrees Fahrenheit.
Remove the pan from the heat and mix in the vanilla extract.
Place the shortbread back into the baking dish, making sure the parchment paper is positioned correctly.
Carefully pour the hot caramel over the cookie layer in one smooth motion.
Allow this to cool on on the counter for about 10 minutes, then place in the fridge to cool for about an hour.
To make the final chocolate layer:
Place the chocolate chips in a medium size microwave-safe bowl.
Heat the heavy cream in the microwave until it is very hot, but not necessarily boiling.
Pour the hot cream over the chocolate chips, then cover the bowl with a plate. Allow this to sit for 5 minutes so that the chocolate can melt.
Then whisk until the chocolate is completely smooth. If it isn't 100% smooth, microwave in 15 second intervals until it is smooth. Then stir in the vanilla extract.
Allow the chocolate to cool for a few minutes before pouring over the caramel layer.
Smooth out with an offset spatula if needed.
Allow the chocolate layer to cool on the counter for 5 to 10 minutes before sprinkling with the finishing salt. If you put the salt on too soon, the salt will dissolve.
Let everything cool on the counter for about 1 hour and then cover tightly and refrigerate, ideally for a minimum of 5 hours but for best results overnight.
When you are ready to serve, remove the bars from the pan and gently pull away the parchment paper from the sides of the bars.
Use a very sharp long knife to slice. Clean the knife off after each slice for perfectly clean cuts.
Store in an airtight container.
If you only have unsalted butter, add a dash of salt.The calories shown are based on the recipe being cut into 16 bars, with 1 serving being 1 bar. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**