Prepare brownies according to package instructions. Pour 1/3 of the batter into the bottom of a 9x13-inch baking pan that has been lined with parchment paper or greased with cooking spray.  Spread the batter so that it forms an even layer to coat the bottom of the pan. 

Lay the pretzels down in an even layer on top of the brownie batter, then add a second even layer of the pretzels and then the rest of the brownie batter. Try and spread it as best as you can. Even if it's not covered all the way the batter on the bottom will rise through the pretzels and the batter on the top will spread.

Once the brownies are out, spoon some caramel sauce onto the top of the brownies. And smooth it out to form an even layer.

Sprinkle with some coarse sea salt.  And then once the brownies have cooled, lift them out of the pan if you used parchment paper for easy cutting and cut them into bars. (Or you can cut them in the pan.) Enjoy!