In a mixing bowl, combine the graham cracker crumbs and melted butter. Stir until the crumbs are thoroughly coated and resemble wet sand.
Press the crumb mixture firmly into the bottom of a 9-inch springform pan to create an even crust. Use the bottom of a glass or measuring cup to pack it tightly. Place the crust in the refrigerator to set while preparing the filling.
In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy. Gradually add in the powdered sugar and vanilla extract, mixing until well combined and there are no lumps.
In a separate bowl, whip the heavy cream until stiff peaks form. Carefully fold the whipped cream into the cream cheese mixture until fully incorporated, taking care not to deflate the whipped cream.
Gently fold in the sliced strawberries into the cheesecake filling, reserving a few for decoration on top.
Pour the cheesecake filling over the prepared crust, smoothing the top with a spatula.
If using strawberry jam, warm it slightly in the microwave until it becomes spreadable, then drizzle over the top of the cheesecake. Use a knife to create swirls for a marbled effect.
Cover the cheesecake with plastic wrap and refrigerate for at least 4 hours, or overnight, to set.
Once set, carefully remove the sides of the springform pan. Decorate the top with the reserved strawberries and garnish with fresh mint leaves.