Preheat your oven to 325 degrees Fahrenheit and prepare a 12-cup muffin tin with paper liners. Set aside.
In a bowl, combine the Oreo crumbs and melted butter until the crumbs are moistened.
Add a heaping tablespoon of the crumb mixture into the bottom of each paper liner and press down to pack the crumbs together to form a crust.
Add the room temperature cream cheese to a large bowl and mix with a hand mixer on medium-high speed until creamy and smooth.
Add the sugar and mix well for about 3 minutes.
Add the sour cream and vanilla, and mix well on low speed until well blended.
Add the eggs one at a time and mix well after each addition, scraping down the bowl to make sure everything is incorporated.
Divide the cream cheese mixture evenly between the 12 prepared cups and pour it in over the crusts.
Add the chocolate (chopped) to a microwave-safe bowl along with the cream. Microwave on 50% power for 30-second intervals until the chocolate is melted.
Add a small dollop of melted chocolate on top of each of the cheesecakes and swirl the chocolate into the cheesecake mixture with a knife or a bamboo skewer.
Bake at 325 degrees Fahrenheit for about 25-30 minutes or until the edges of the cheesecakes are set and the middles have a slight jiggle.
Let the cheesecakes cool at room temperature until cooled, and then chill them for at least 3 hours or overnight.
Serve with some fresh berries and whipped cream (optional), or some additional shaved chocolate.