Line your 9x9 inch pan with parchment paper, leaving some overhang for easy removal.
Combine the graham cracker crumbs with the melted butter in a bowl, mixing until the crumbs are evenly coated and resemble wet sand.
Press the crumb mixture firmly into the prepared pan, creating an even crust on the bottom. Chill in the refrigerator for about 15 minutes to set.
In a large bowl, beat the softened cream cheese with sugar until smooth and creamy, about 2 minutes. You want it to feel soft and velvety.
Stir in the lemon juice and vanilla extract until combined; the mixture will become fragrant and slightly zingy.
In a separate bowl, whip the chilled heavy cream until soft peaks form, listening for gentle swooshes and watching it increase in volume.
Gently fold the whipped cream into the cream cheese mixture in thirds, carefully combining until smooth and fluffy without deflating the airiness.
Pour the creamy filling over the chilled crust, smoothing the top with a spatula for an even surface. Cover with plastic wrap.
Refrigerate the assembled bars for at least 4 hours, preferably overnight, until the filling is firm and set.
Once chilled, lift the cheesecake out of the pan using the parchment overhang. Slice into squares with a sharp knife dipped in hot water for clean cuts.
Serve the bars chilled, perhaps topped with fresh berries or a drizzle of chocolate for extra indulgence.
