For the Crust:
Preheat oven to 350°F (180°C). Line a cupcake tins with cupcake liners.
Add oreo cookies to your food processor and pulse until broken into small pieces. 12 Oreo cookies
Add melted butter and pulse to combine. 2 ½ tablespoons (71 g) unsalted butter
Use about a tablespoon to transfer the mixture to your cupcake tin. Press into a flat layer. A shot glass works great but any flat tool, or even clean hands work!
Bake for 5 minutes. Remove from the oven and set aside. Lower the oven temp to 325°F (163°C).

For the filling:
Make the filling. Combine the heavy cream and chocolate in a small saucepan or in a microwave-safe bowl. Heat, stirring frequently, until the chocolate melt and the mixture is smooth. If doing this in the microwave, heat for 30 seconds at 50% power, stirring in between. ¼ cup (60 ml) heavy cream 6 ounces semisweet chocolate
Beat cream cheese and sugar. In a large mixing bowl (I like to use my stand mixer with my paddle attachment) beat together the cream cheese and sugar at low speed, until thoroughly combined. Scrape the bottom and sides of the bowl with a spatula and beat until smooth. 12 ounces cream cheese ½ cup (100 g) granulated sugar
Add eggs. Add the eggs one at a time, beating to combine. Scrape down the bowl as needed. 2 large eggs
Add vanilla and cocoa. Stir in the vanilla, then the cocoa powder. 2 teaspoons vanilla extract 1 tablespoon cocoa powder
Add melted chocolate mixture. Add the chocolate/cream mixture, beating on low speed until thoroughly combined. Scrape the bottom and sides of the bow with a spatula; and beat to combine briefly, just until smooth.
Divide the batter between the 12 cupcake liners. Use a small ice cream scoop to transfer the cheesecake mixture to your cupcake tin. Fill up to the top. I like to use a small cookie scoop for this. Smooth the top with a spatula.
Bake for 20-25 minutes. Remove from the oven and cool to room temperature for one hour then refrigerate for 2 hours or until firm. Remove from the muffin tin.

Make the ganache
Heat heavy cream. Place the chocolate in a small mixing bowl. Heat the cream until very hot, either in saucepan on low heat, or in the microwave. You want the heavy cream hot, but not boiling. ¼ cup (60 ml) heavy cream 3 ounces semisweet chocolate
Combine chocolate and cream. Pour the hot cream over the chocolate. Let sit for 5 minutes, then whisk smooth.
Top cheesecakes. Spread a little ganache over the top of each cheesecake. Return the cheesecakes to the fridge to firm up before serving

Notes
Storage: You can make mini cheesecakes ahead of time. Once the cheesecakes have cooled completely, refrigerate them in an airtight container for up to 2 days.
Freezing: You can freeze mini cheesecakes. Once the cheesecakes have cooled completely, wrap them individually in plastic wrap and then place them in a freezer-safe bag or container. Freeze the cheesecakes for up to 3 months. To thaw, let the cheesecakes sit in the refrigerator overnight.