Place the graham crackers in a zip-top bag and crush them with a rolling pin until fine crumbs form, about 1-2 minutes.
Transfer the crumbs to a mixing bowl and stir in the melted butter until the mixture resembles damp sand.
Press this crumb mixture firmly into the bottom of your prepared baking dish, creating an even, compact layer. Chill in the fridge for 15 minutes to set.
In a large bowl, beat the softened cream cheese until smooth and fluffy, about 2-3 minutes.
Add the powdered sugar and vanilla extract to the cream cheese and mix until well combined and creamy.
Pour in the lemon juice and mix again, just until incorporated. The mixture should be bright and smooth, with a slight aroma of citrus.
Spread the cream cheese filling evenly over the chilled crust, smoothing the top with a spatula.
Cover the dish with plastic wrap or foil and refrigerate for at least 4 hours or overnight to allow the filling to set firm and flavors to meld.
Once fully chilled and set, lift the bars out using parchment paper, cut into squares, and serve chilled, garnished with berries or a drizzle of chocolate if desired.
