Preheat and Prep: Preheat oven to 350°F (175°C). Line 12 muffin tins with paper liners.

Make Crust: In a large resealable plastic bag or a food processor fitted with a metal blade, crush or blend the OREO®s until fine crumbs form. Transfer the crumbs to a bowl and pour in the melted butter. Stir until the crumbs are completely coated and moistened. Press about 1 tablespoon of the crumb mixture into the bottom of each liner.

Make Cheesecake Filling: In a large bowl using a hand mixer (or in the bowl of a stand mixer using the paddle attachment), beat the softened cream cheese, sugar, flour, cocoa powder, and salt until light and fluffy. Add the eggs and beat until well combined. Fold in the melted bittersweet chocolate.

Fill Crusts: Pour the cheesecake filling over the crust in the prepared liners.

Bake: Bake the cheesecakes until only slightly jiggly in the center, 12 to 14 minutes.

Cool: Let the cheesecakes cool for 5 minutes in the pan and then transfer them to a rack to cool completely. Refrigerate until cold, at least 1 hour.

Make Chocolate Ganache: Once the cheesecakes are cold, make the chocolate ganache. Add the chocolate chips and heavy cream to a microwave-safe dish. Microwave in 10-second intervals, stirring in between, until the chocolate is melted. Stir until smooth and creamy.

Top with Ganache: Spread about 1 tablespoon of the chocolate ganache on top of each cheesecake. Return them to the refrigerator to let the chocolate sauce set, about 10 more minutes.

Make Chocolate Whipped Cream: While the ganache is setting, make the chocolate whipped cream. In a large bowl, beat the heavy cream with the chocolate syrup until stiff peaks form, about 4 minutes.

Pipe and Garnish: Transfer the chocolate whipped cream to a piping bag fitted with a star tip (or use a spoon). Top each cheesecake with the chocolate whipped cream and garnish with a piece of Hershey’s® chocolate.