Prep your pan: Line an 8x8 or 9x9-inch square pan with parchment, leaving a slight overhang for easy lifting. This helps when slicing and serving.
Beat the cream cheese: In a large bowl, beat softened cream cheese until smooth and fluffy, about 1–2 minutes.
No lumps means a silkier filling.
Mix in the liquids: Add sweetened condensed milk, lemonade concentrate, lemon juice, vanilla, salt, and lemon zest. Beat on medium speed until fully combined and silky.
Fold in the whipped topping: Gently fold in the whipped topping with a spatula until no streaks remain. Don’t overmix—keep it airy.
Layer 1: Arrange a single layer of graham crackers on the bottom of the pan, breaking pieces to fit as needed.
Aim for full coverage.
Add filling: Spread about one-third of the lemon mixture over the grahams. Smooth the top with an offset spatula or the back of a spoon.
Repeat layers: Add another layer of graham crackers, then another third of the filling. Repeat once more for a total of three layers of filling and three layers of grahams, ending with the filling on top.
Chill: Cover the pan tightly and refrigerate for at least 6 hours, preferably overnight.
The longer it chills, the better the texture.
Garnish: Just before serving, add extra whipped topping if desired, and garnish with lemon zest, crushed grahams, thin lemon slices, or berries.
Slice and serve: Lift the cake out using the parchment overhang. Cut into squares with a sharp knife, wiping the blade between cuts for clean slices.