Preheat your oven to 350°F (175°C). Prepare an 8-inch baking dish by greasing it or lining it with parchment paper.

Melt ½ cup of unsalted butter in a microwave-safe bowl. Stir in 1 cup of granulated sugar, 2 large eggs, and 1 teaspoon of vanilla extract until well combined.

In a separate bowl, whisk together ½ cup of unsweetened cocoa powder, 1 cup of all-purpose flour, ½ teaspoon of salt, and ½ teaspoon of baking powder.

Gently fold the dry ingredients into the wet mixture until no flour streaks remain. Do not overmix.

Pour the batter into the prepared baking dish and bake for 30-35 minutes, until a toothpick comes out with a few moist crumbs.

Let the brownies cool completely in the pan on a wire rack.

For the frosting, dissolve 2 tablespoons of instant coffee granules in ¼ cup of heavy whipping cream. Beat ½ cup of softened unsalted butter until fluffy, then gradually add 2 cups of powdered sugar and the coffee mixture.

Once cooled, spread the coffee frosting evenly across the top of the brownies.

Slice the frosted brownies into squares or rectangles and serve.