Preheat oven to 325 degrees.
Combine sugar, salt, and water in a sauce pan over medium heat. Cook until sugar fully dissolves and begins to caramelize. Be sure to stir mixture constantly. Remove from heat when color becomes a golden amber.
Slowly add heavy cream and stir until combined. Then add butter and stir until melted; mix in salt and vanilla. Allow caramel to cool slightly before adding to brownies.
Whisk eggs in a mixing bowl. Add oil and water and continue mixing until well blended.
Add dry brownie mix and mix until fully incorporated.
Spray an 8x8” square baking pan with nonstick cooking spray. Pour brownie mix into pan and spread evenly.
Scatter dollops of caramel sauce into the pan and use the tip of a knife to swirl it into the brownie batter.
Drop chocolate chunks on top of brownies and press lightly to stick them into the batter.
Bake for 18-22 minutes, or until toothpick inserted into the center of the brownies comes out clean. Cool completely before cutting into squares.