Step-by-Step Instructions

• Preheat the oven to 325°F (165°C). Lightly spray a 9x13 inch baking dish with baking spray. You can also line it with parchment paper for easier lifting and cutting.
• In a food processor, pulse the Oreo cookies until fine crumbs form. Add the 4 tablespoons of melted butter and pulse again until the mixture resembles wet sand.
• Press the Oreo mixture evenly into the bottom of the baking dish. Use the bottom of a flat measuring cup to compact the crust. Set aside.
• Place the semisweet chocolate chips in a microwave-safe bowl. Heat in 30-second increments, stirring after each burst, until smooth. This usually takes about 90 seconds total. Set aside to cool slightly.
• In a stand mixer fitted with the paddle attachment, beat the softened cream cheese, sugar, and flour on medium speed until smooth. Scrape down the sides of the bowl at least once.
• Add the eggs one at a time, mixing on low speed after each addition just until incorporated. Avoid overmixing.
• With the mixer running on low speed, slowly pour in the melted chocolate. Continue mixing until the filling is uniform in color.
• Add the sour cream and vanilla extract. Mix gently until smooth, then pour the filling over the crust and spread it into an even layer.
• Bake for 50 minutes or until the edges are set and the center has a slight jiggle. The bars will firm up as they cool.
• Remove from the oven and let cool to room temperature, then chill completely in the refrigerator before slicing. This step is essential for clean cuts.