Preheat the oven to 160°C. Spray an 8-inch square baking pan with nonstick baking spray.
For the brownie batter: 1. Place the chocolate in a microwave-safe bowl. Melt the chocolate in the microwave in 30-second increments, being careful not to let it burn. Set it aside to cool slightly.
2. In a medium mixing bowl, cream the butter and granulated sugar. Beat in the eggs. With the mixer on low speed, drizzle in the melted chocolate. Add the vanilla extract and mix. Add the flour to the bowl and mix just until combined; do not over mix.
3. Pour the batter in the prepared baking pan. Spread it to even out the surface. Bake until the center is no longer soft, 40 to 45 minutes. Set the brownies aside to cool completely before icing.
For the icing: 1. In a large mixing bowl, combine the butter, powdered sugar, cocoa powder, salt and vanilla. Mix until slightly combined, then add 1/2 cup of the coffee. Whip until the icing is light and fluffy. If the icing is overly thick, add 1/4 cup more coffee. It should be very light and fluffy.
2. Ice the cooled brownies, spreading the icing on thick. Refrigerate until the icing is firm, and then slice the brownies into squares.
Cook Notes: Can also serve in a bowl topped with coffee ice cream and hot fudge sauce. Sinful!