Step 1: Preheat your oven to 350°F (175°C). Grease and line a 9x13-inch baking pan with parchment paper, leaving some overhang for easy removal.
Step 2: In a double boiler or a microwave-safe bowl, melt the unsalted butter and chopped dark chocolate together until smooth. Stir frequently to avoid burning. Once melted, remove from heat and let it cool slightly.
Step 3: In a large mixing bowl, whisk together the eggs, granulated sugar, vanilla extract, brewed coffee, and instant espresso granules until well combined. Add the melted chocolate mixture and mix until smooth.
Step 4: In another bowl, whisk together the flour and salt. Gradually fold the dry ingredients into the wet mixture until just combined. Be careful not to overmix!
Step 5: Gently fold in half of the salted caramel sauce and the mini semi-sweet chocolate chips into the brownie batter. This will create delicious pockets of caramel and chocolate throughout.
Step 6: Pour the brownie batter into the prepared baking pan, spreading it evenly. Drizzle the remaining caramel sauce on top, and use a toothpick or knife to swirl it into the batter gently.
Step 7: Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs (not wet batter).
Step 8: Once baked, remove from the oven and let the brownies cool in the pan for about 15 minutes. Then, use the parchment overhang to lift them out of the pan and onto a wire rack to cool completely. Cut into squares and enjoy!