Preheat oven to 350
Line a square baking pan with parchment paper
In a bowl mix together the brownie mix, eggs, oil and hot water
Add the chocolate chips, mix
Heat a small saucepan over medium heat, add the butter, brown sugar, half and half, vanilla and salt
Bring to a bubble, whisking for 5 minutes (turn the heat down if its boiling too rapidly)
Add the baking soda, it will foam up
Turn the heat down to low and whisk
Pour 3/4 of the brownie batter into the baking pan
Pour in the caramel, keeping it away from the edges
Pour the rest of the brownie mixture on top
Bake for 50 minutes or until the internal temperature of the brownies reach at least 180 degrees
Remove from the oven, let the brownies cool for at least 2 hours on a cooling rack before taking out of the pan. I find the best texture is to let them cool 6 hours before cutting in to them, this gives them time to fully set up.
Cut in to squares and serve!