Preheat the oven to 350°F (175°C) and grease a 9x13 inch baking pan or line with parchment paper for easy removal.
In a medium saucepan, melt the butter over low heat. Once melted, remove from heat and stir in the granulated sugar until smooth.
Let the butter mixture cool slightly, then whisk in the eggs one at a time, followed by the vanilla extract and instant coffee granules. Mix until well combined.
In a separate bowl, sift together the flour, cocoa powder, baking powder, and salt. Gradually add the dry mixture to the wet ingredients, stirring until just combined. Avoid overmixing.
Fold in the chocolate chips gently, ensuring they are evenly distributed throughout the batter.
Pour half of the brownie batter into the prepared baking pan, spreading it evenly with a spatula.
Drizzle half of the caramel sauce over the brownie layer, then gently swirl it through with a knife for a marbled effect.
Pour the remaining brownie batter over the caramel, spreading it evenly, and drizzle with the remaining caramel sauce on top. Swirl again if desired.
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).
Remove from the oven and let cool in the pan for at least 15-20 minutes. If desired, sprinkle with sea salt flakes for an extra flavor dimension.
Once cooled, slice into squares and enjoy!
Notes
For an extra flavor dimension, sprinkle with sea salt flakes before serving.