In a large mixing bowl, beat the softened cream cheese on medium speed for 1-2 minutes until completely smooth and creamy with no lumps. This is crucial because any remaining lumps will texture your finished pie. I like to scrape down the bowl halfway through to ensure everything gets incorporated evenly.

Reduce mixer speed to low and gradually add the sweetened condensed milk to the cream cheese base, blending until smooth. Then add the freshly squeezed lemon juice, lemon zest, vanilla extract, and kosher salt. Mix on low speed until everything is well combined and the filling is thick and creamy—this should take about 1-2 minutes. The acid from the lemon juice will slightly thicken the mixture, so don't overmix or you risk overworking the cream cheese.

Gently fold the whipped cream into the lemon filling using a spatula with a few careful strokes until just combined—you want to maintain some of the airiness for a light, mousse-like texture. Pour the filling into the graham cracker crust and spread evenly. Cover the pie loosely with plastic wrap and refrigerate for at least 2 hours, or up to overnight, until it's set and chilled through.

Remove the pie from the refrigerator about 10 minutes before serving—this allows the flavors to brighten slightly while keeping the texture perfectly set. Slice with a sharp knife dipped in warm water and wiped clean between cuts for clean edges. Serve chilled, optionally topping each slice with a dollop of extra whipped cream or a thin lemon wheel for garnish.