Marbled Brownies - unsalted butter

Method

• Position a rack in the middle of the oven and preheat to 350 degrees F. Line a 9 by 13-inch baking pan with parchment paper, so that the edges of the paper come up the sides.
• Lightly butter the paper.
• Put both the semisweet and unsweetened chocolates and the butter in a heatproof medium bowl.
• Fill a medium saucepan with a couple inches of water and bring to a simmer over medium heat.
• Turn off the heat; set the bowl of chocolate over the water to melt.
• Whisk until smooth.
• (Alternatively, melt in a microwave at half power, for 1 minute, stir and then heat for another minute or until melted.)
• Whisk the flour and salt in a bowl.
• In a large bowl whisk together the eggs, sugar, and vanilla.
• Stir the chocolate mixture into the egg mixture until smooth.
• Add the dry ingredients and mix until just blended.
• Take care not to over mix the batter.
• Transfer the batter to the prepared pan.
• For the marble swirl: Whisk the cream cheese with the sugar, egg, and vanilla until smooth.
• Drop very large spoonfuls of the cream cheese mixture onto the surface of the brownie batter.
• Insert a butter knife through the batter to the bottom of the pan.
• With the flat edge of the knife, make swirling motions through the batters, occasionally lifting the knife through the top, until the dark and light batters are marbled.
• Bake until a toothpick inserted into the center of the brownies comes out coated with a fudge-y crumb, 30 to 35 minutes.
• Cool the brownies in the pan on a rack.
• To take the brownies out of the pan, lift the edges of the paper.
• Cut the brownies into squares.
• Serve.