• Preheat oven to 350°F. Spray a 7×11 inch pan with baking spray. Line with parchment paper if desired.
• To a large microwave safe bowl, add butter and chocolate chips and microwave for 30 seconds then stir. If not melted, microwave at 10 second intervals, stirring in between each until just melted.
• Stir in cocoa powder. Then add sugars, stir until well combined.
• Add eggs and egg yolk one at a time, stirring well after each addition.
• Stir in vanilla extract and salt. Then add flour and stir until well mixed.
• Set aside ¼ cup of the batter, and spread remaining batter into prepared pan.

Cream Cheese Mixture

• To a medium bowl, add cream cheese and sugar, and beat with an electric mixer for 1 to 2 minutes, until creamy.
• Mix in egg and vanilla until well combined.

Assembly

• Pour cream cheese mixture over brownie batter in the pan. With a spoon, drop or drizzle reserved ¼ cup brownie batter over the cream cheese mixture.
• Using a knife, swirl brownie batter into the cream cheese mixture.
• Bake for 27-35 minutes, or until the center is set and a toothpick inserted in the center comes out mostly clean with a few fudgy crumbs.
• Cool completely before cutting and serving.