Make the Whipped Cream:
In a large mixing bowl, beat the heavy whipping cream, powdered sugar, and vanilla extract with an electric mixer on medium-high speed until stiff peaks form.
Layer the Cake:
Spread a thin layer of whipped cream on the bottom of a 9x13-inch dish (to keep the cookies from sliding).
Place a single layer of Oreos on top, breaking some to fit.
Continue Layering:
Spread ⅓ of the whipped cream evenly over the cookies. Repeat layers—Oreos, whipped cream—until you end with whipped cream on top (usually 3–4 layers total).
Garnish:
Sprinkle crushed Oreos or chocolate shavings over the top for decoration.
Chill:
Cover with plastic wrap and refrigerate for at least 6 hours, or preferably overnight, until the Oreos soften to a cake-like texture.