Make the Crust: Crush the Oreo cookies into fine crumbs using a food processor or Thermomix. Mix the crumbs with melted butter until evenly combined. Divide the mixture evenly among 12 lined muffin cups and press firmly into the bottoms using the back of a spoon.
Bake: Preheat your oven to 350F (175C). Bake the crust for about 5 minutes. This quick bake helps set the crust, giving it a nice crunch. Once done, remove the tin from the oven and let it cool completely. Patience is key here; a cool crust is essential for the mousse.
Prepare the Mousse: Beat the softened cream cheese until completely smooth. Add powdered sugar and vanilla extract and mix until creamy. In a separate bowl, whip the heavy cream until stiff peaks form. Fold the whipped cream gently into the cream cheese mixture. Finally, fold in crushed Oreo cookies.
Assemble: Spoon the mousse evenly over each chilled crust. Fill each liner to the top, making sure they're all evenly filled.
Refrigerate: Place the muffin tin in the refrigerator and let the cakes set for at least 4 hours, or overnight for the best texture. This allows the mousse to firm up.
Decorate: Before serving, top each mini cake with: Whipped cream, mini Oreo, Oreo crumbs, and chocolate ganache or shavings.
