In a large mixing bowl, whip the heavy cream until soft peaks form. Gradually add in the powdered sugar and vanilla extract, continuing to whip until stiff peaks form.
Prepare a 9x13 inch baking dish. Begin layering by placing a single layer of chocolate graham crackers on the bottom of the dish.
Spread a generous layer of the whipped cream mixture over the graham crackers, smoothing it out evenly.
Add a layer of sliced strawberries on top of the cream. Sprinkle a portion of the dark chocolate shavings over the strawberries.
Repeat the layering process: graham crackers, whipped cream, strawberries, and chocolate shavings until all ingredients are used, finishing with a layer of whipped cream on top.
Cover the dish with plastic wrap and refrigerate for at least 4 hours, or overnight for the best results. This allows the flavors to meld and the graham crackers to soften.
When ready to serve, remove from the fridge and optionally garnish with fresh mint leaves for a pop of color. Cut into squares and enjoy!