Begin by preparing your whipped cream. In a large mixing bowl, combine the heavy whipping cream, powdered sugar, and vanilla extract.
With an electric mixer, beat the cream mixture on high speed for about 3-5 minutes, until stiff peaks form.
Take an 8x8 inch baking dish and start layering the cake. Briefly dip each Oreo cookie into the chocolate syrup, ensuring they are coated but not soaked.
Arrange the dipped Oreos in a single layer at the bottom of your baking dish, covering the bottom completely.
Carefully spread an even layer of the whipped cream mixture over the Oreos, smoothing it out with a spatula.
Repeat the layering process: add another layer of dipped Oreos followed by another layer of whipped cream.
Once layered, cover the dish tightly with plastic wrap and place it in the refrigerator. Chill for a minimum of 4 hours, but overnight is ideal.
Just before serving, sprinkle the top generously with crushed Oreos and add fresh mint leaves if desired.
Notes
Serve chilled and consider adding a drizzle of chocolate syrup for extra indulgence.