Preheat the Oven: Preheat oven to 350°F (175°C). Line an 8x8 baking pan with parchment paper.
Mix Wet Ingredients: In a bowl, whisk together melted butter, sugar, eggs, and vanilla extract until smooth.
Add Dry Ingredients: Stir in cocoa powder, flour, baking powder, and salt until just combined.
Add Coffee & Chocolate: Mix in brewed coffee and chocolate chips until fully incorporated.
Bake: Pour the batter into the prepared pan and bake for 30 minutes or until a toothpick comes out clean.
Cool: Let brownies cool completely on a cooling rack.
Make the Drizzle: In a small saucepan, heat the heavy cream and coffee over medium heat until warm. Stir in powdered sugar.
Top the Brownies: Drizzle the mocha frappuccino mixture over the cooled brownies and top with melted chocolate chips.
Serve: Slice and enjoy the decadent mocha experience.