Line your square pan with parchment paper for easy removal and set aside.
Place the graham crackers in a zip-top bag and crush them with a rolling pin until you have fine, slightly coarse crumbs that smell toasty and sweet.
Melt the butter gently in the microwave or on the stove until just shimmering, about 30 seconds in the microwave.
Mix the crushed graham crackers with the melted butter until all the crumbs are evenly coated, resembling wet sand.
Press the buttery crumbs firmly into the bottom of your prepared pan, creating an even crust. Chill in the refrigerator for about 10-15 minutes to set.
In a mixing bowl, beat the softened cream cheese with a spatula or hand mixer until smooth and fluffy, about 2 minutes, until no lumps remain.
Add the sweetened condensed milk, lemon juice, and vanilla to the cream cheese, and mix until the filling is thick, creamy, and well combined.
Pour the luscious filling over the chilled crust and spread evenly with a spatula, smoothing out the surface.
Cover the pan loosely with plastic wrap and refrigerate for at least 4 hours or overnight, allowing the filling to firm up and flavors to meld beautifully.
Once set, lift the bars out of the pan using the parchment paper and cut into neat squares with a sharp knife, wiping the blade clean between slices for clean edges.
Serve chilled, garnished with fresh berries or a drizzle of chocolate if you like, and enjoy the creamy, tangy bites.
