Preheat oven to 350 degrees F. Line an 8-inch square baking pan with parchment paper and grease with butter.
In a medium bowl, combine melted butter, chocolate chips, brown sugar, and salt. Stir until everything is well combined.
In a separate bowl, whisk together eggs, flour, espresso powder, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and mix until fully incorporated.
Spread the batter into the prepared baking pan and bake for 25-30 minutes or until a toothpick inserted into the center comes out clean.
Remove from oven and allow to cool completely before adding the caramel topping.
Once cooled, spread the caramel sauce evenly over the top of the brownies. Cut into squares and enjoy!