In a large mixing bowl with a hand mixer or in the bowl of a stand mixer, combine the heavy cream, powdered sugar, and vanilla extract. Turn the mixing speed on low, then gradually turn the speed up to high.
Beat until stiff peaks form. Set ½ cup of whipped cream aside. In a medium mixing bowl, beat the cream cheese until smooth. Fold the remaining whipped cream into the cream cheese.
Spread a thin layer of the cream cheese/whipped cream mixture into the bottom of a 9X9-inch baking dish. Place a layer of graham crackers over the top, then spread half of the cream cheese/whipped cream mixture over top.
Place 1 cup of berries into the mixture. Repeat. Top with the final layer of graham crackers, then spread the reserved whipped cream over top. Place the final cup of berries over top.
Garnish with fresh mint, if desired. For patriotic holidays, you can always create a flag pattern on top!