This is a dense, moist brownie. You can use semisweet chocolate rather than bittersweet and the results are just as delicious.
- Preheat the oven to 375 degrees.
- Butter an 8-inch-square pan.
- In an electric mixer, combine the eggs and sugar.
- Beat until light and fluffy.
- In a medium saucepan over medium heat, melt the bittersweet chocolate, white chocolate and butter, stirring until smooth.
- Remove from heat and beat into the egg mixture.
- Sift the flour and cocoa together and beat into the chocolate mixture.
- Whisk in the Guinness.
- Pour into the pan and bake for 20 to 25 minutes, or until a skewer inserted in the center comes out almost clean.
- Remove from the oven and let cool on a wire rack.
- To serve, dust the cake with confectioners' sugar and cut into squares.