Instructions

• Preheat the oven to 350°F. Line a 9x13-inch baking pan with heavy-duty aluminum foil leaving at least a 2-inch overhang on two opposite sides; spray the foil lightly with nonstick baking spray. Set the pan aside.
• Place the full package (36) Oreo cookies in a food processor and process to fine crumbs. (If you don't have a food processor, place the cookies in a heavy-duty resealable bag and crush with a rolling pin until fine.)
• Transfer the cookie crumbs to a large bowl, add 6 tablespoons (85 g) melted unsalted butter, and mix until the crumbs are evenly moistened.
• Press the crumb mixture firmly and evenly into the bottom and slightly up the sides of the prepared pan. Bake the crust at 350°F for 10 minutes. Remove from the oven and set the pan on a cooling rack. Immediately reduce the oven temperature to 325°F.
• In the bowl of a large food processor, combine 24 ounces room-temperature cream cheese and 3/4 cup (171 g) room-temperature sour cream. Pulse/process until completely smooth, stopping to scrape the bowl as needed.
• Add 1 1/4 cups (249 g) granulated sugar, 1 tablespoon (14 ml) vanilla extract, and 1/2 teaspoon espresso powder to the cream cheese mixture and process until smooth, scraping the sides and bottom of the bowl as necessary.
• With the processor running on low speed, add the 3 large room-temperature eggs and 2 large room-temperature egg yolks and blend just until combined. Do not overmix.
• Stop the processor, remove the blade (or transfer the batter to a large bowl), and using a rubber spatula fold in 3/4 cup (171 ml) Baileys Irish Cream until just incorporated. Fold in 2 teaspoons all-purpose flour until combined.
• Pour the filling over the prepared crust and spread into an even layer.
• Confirm the oven is at 325°F, then bake the cheesecake bars for about 40 minutes, or until the edges are set and the center is still slightly jiggly.
• Turn off the oven, crack the oven door, and let the pan cool inside the oven for 10 minutes. Remove the pan and transfer to a wire rack to cool to room temperature. Refrigerate the bars for at least 4 hours or overnight.
• For the ganache: place 6 ounces (170 g) finely chopped semi-sweet chocolate in a heatproof bowl.
• In a small saucepan over medium heat, bring 1/2 cup (113 ml) heavy cream just to a rolling simmer, then immediately remove from heat. Pour the hot cream over the chopped chocolate and let sit for 1 minute.
• Whisk the chocolate and cream together until smooth and glossy, then stir in 3 tablespoons (42 ml) Baileys Irish Cream. Let the ganache cool until tepid.
• Pour the tepid ganache over the chilled cheesecake bars and spread evenly. Refrigerate until the ganache is set but still creamy, about 1 hour.
• When ready to serve, use the foil overhang to lift the cheesecake slab from the pan and transfer it to a cutting board. Using a large, sharp knife, slice into squares, wiping the knife clean with a damp cloth between cuts. Serve.