In a large bowl, whip the heavy cream until stiff peaks form. Gradually add the granulated sugar and vanilla extract, continuing to whip until well combined.
Arrange a layer of graham cracker squares in the bottom of a 9x13 inch baking dish.
Spread a layer of the whipped cream mixture over the graham crackers. If using, add a layer of sliced strawberries.
Repeat the layering process: graham crackers, whipped cream, and strawberries, until all ingredients are used, ending with a layer of whipped cream.
Drizzle the melted butter over the top layer of whipped cream. You can also top with extra strawberries or graham cracker crumbs.
Cover the dish with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the cookies to soften and the flavors to meld.
Slice and serve chilled.
Notes
This icebox cake is best served cold and can be customized with different fruits like blueberries or raspberries.