Preheat oven to 350º F. Generously butter a 9-inch square metal baking pan. Add a layer of parchment paper, leaving the edges long enough to lift the brownies out of the pan once cool for easier slicing. Butter the parchment paper, pressing it down to help it adhere smoothly to the pan. Set aside.
To prepare the brownies, melt chocolate and butter together in a double boiler or in short bursts in the microwave. While still warm, mix in espresso powder and Kahlua, stirring until well combined. Set aside.
In a medium-sized mixing bowl, combine sugar, salt, and eggs. Mix well with a wooden spoon. Add chocolate mixture and chocolate chips, stirring until well combined. Gently stir in flour, taking care not to over mix.
Pour the batter into the prepared pan and bake for 25 minutes. Remove from the oven and cool to room temperature.
To prepare the frosting, combine confectioners' sugar, salt, melted butter, and Kahlua in the bowl of a standing electric mixer. Beat until smooth. Spread the frosting evenly over the cooled brownies.
For the glaze, melt bittersweet chocolate and butter together in a double boiler or in the microwave. Once melted, mix in Kahlua until well combined. Drizzle glaze over the frosted brownies.
Refrigerate until well chilled. Lift the brownies from pan using the parchment paper and slice into 1 1/2-inch squares. Serve chilled or at room temperature.