Preheat the oven to 350°F/ 175°C and line an 8x8 baking pan with aluminum foil or grease it and line with parchment paper. Make sure that the paper or foil overhangs so you can easily lift the brownies out.
Whisk together all of the Oreo cheesecake ingredients in a medium bowl and set aside.
½ cup sugar, 8 oz cream cheese, 1 egg, 1 teaspoon vanilla extract, 1 tablespoon all purpose flour, 8 Oreos
Melt the butter in a large microwave safe bowl. Once melted, add your chopped chocolate. Let the chocolate sit for a few minutes and then stir until it is completely melted. If the chocolate still hasn't melted, place the bowl back in the microwave and melt in 10 second increments, stirring after every 10 seconds.
¾ cup unsalted butter, 4 oz dark chocolate
In a stand mixer fitted with the whisk attachment, or in a large bowl with a handheld mixer, whisk the oil, sugar, light brown sugar, eggs, egg yolk and vanilla extract for 5 minutes on medium-high speed. This will give you a crinkly top for the brownies!
2 eggs, 1 egg yolk, ¼ cup vegetable oil, ½ cup sugar, ½ cup light brown sugar, ¾ teaspoon vanilla extract
Add your cocoa powder to the melted chocolate and fold until it is completely smooth.
¼ cup cocoa powder
Pour the sugar mixture into the melted chocolate butter mixture and use a rubber spatula to fold everything together. Pour in the flour and salt and fold until there are no more streaks of flour. Stir in the white chocolate chips
½ cup all purpose flour, 1 teaspoon kosher salt, ½ cup white chocolate chips
Pour ¾ of the batter into the prepared pan. Spread the cheesecake mixture on top until it covers the surface, then dollop the reserved brownie mixture on. Use a butter knife or toothpick to create the swirls - make sure not to swirl too much!
Bake for 30-35 minutes. Allow the brownies to cool completely before slicing.
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. Room Temperature: I make sure that all of my ingredients are at room temperature before I start the recipe, so pull out all of the ingredients about 2 hours before you start baking.Salt: If you don’t have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt.Butter: I use European style butter, like Kerry Gold, in my recipes. This will make your finished bake much creamier and richer.Cream Cheese: if your cream cheese only comes in tubs instead of packets, pat it down with a paper towel to remove extra moisture.Storage: keep in an airtight container in the fridge for up to 5 days. You can freeze the bars for up to 3 months. Let them defrost in the fridge overnight before eating.