line an 8x8 inch pan with parchment paper leaving overhang

mix graham cracker crumbs butter sugar and salt until evenly moistened

press firmly into the pan in an even layer

refrigerate 15 minutes while you make the filling.

beat cream cheese until smooth

mix in sweetened condensed milk then lemon juice zest and vanilla until thick and fully combined

whip heavy cream with powdered sugar if using to medium stiff peaks then fold into lemon mixture until no streaks remain

spread filling over chilled crust and smooth the top.

cover and refrigerate until set at least 4 hours or overnight

lift out using parchment overhang and slice into bars with a clean knife wiping between cuts

garnish with lemon zest or slices and keep chilled until serving.