Preheat the oven to 350°F (180°C).
Prepare a 9x9 pan by lining it with parchment paper or spraying it with non stick spray.
Measure out the chocolate chips/chopped chocolate into a bowl. Set aside.
In the bowl of a stand mixer, cream together the butter and sugars until smooth, light in color and fluffy. This will take a few mintues.
Scrape the sides of the bowl and mix in the egg and vanilla.
Once completely combined, stop the mixer and add in the flour, baking soda and salt.
Start mixing slowly, once the flour mixture is about half way incorporated into the dough, pour the chocolate chips/ chopped chocolate into the mixer and allow everything to mix together.
Stop the mixer as soon as the flour is completely incorporated. Avoid over mixing. Set the cookie dough aside.
In a medium sauce pan over medium heat, stir to combine the caramels and sweetened condensed milk until smooth. Remove from heat and set aside.
Divide the dough in half and press half into the bottom of your prepared 9x9 pan.
Pour the caramel mixture on top of the cookie dough. Spread until evenly covered.
Take large portions of the remaining cookie dough, flatten them in your hand and then place on top of the caramel.
Bake in your 350°F (180°C) oven for 25-35 minutes, or until the top is golden brown and the center is just set.
Sprinkle with sea salt, if desired.
Let the cookie bars cool COMPLETELY before cutting.
Cut the bars into your desired size and serve.
Store in an air tight container for up to 3 days.