Prepare the base
Melt the chocolate drops au bain-marie (also known as water bath). Let it cool completely and set aside (room temperature).
Crush the Oreo together with the melted butter until blended well.
Prepare the Cookie Base
Place the cupcake papers on the baking pan. Fill with a layer of cookie dough about 15 g of cookie dough to each liner.
Wrap some film around a glass and press it flat (this way you avoid sticking and press everything well firm and flat). Repeat the process for all liners.
Make the cream cheese batter
Add the cream cheese to a deep bowl and whisk for a minute. Add the sugar and vanilla sugar, then beat together for another 2 minutes. Add the eggs one at a time, beating until each egg is fully incorporated. Add the melted chocolate and mix well.
Lastly, add the sour cream and beat together for 1 minute until well blended.
Fill and Bake the Cheesecakes
Add the cream cheese batter into a piping bag and pipe it on top of the cookie dough.
Place the cupcakes in a preheated oven at 150℃ for about 18 minutes.
Cool and Chill
The center of the cheesecake should be wobbly when it comes out of the oven. Do not bake too long, as it may start to dry out and crack. Place the cupcakes in the turned-off oven to cool for about an hour or until the oven has cooled. Wait for them to reach room temperature before putting them in the refrigerator; this takes about 2 hours. Cover and store in the refrigerator for at least 3 hours, preferably overnight.
