Combine graham cracker crumbs and melted butter in a bowl until the mixture looks like damp sand.
Firmly press the crumb mixture along the base and sides of a 9-inch tart pan, then place it in the freezer for 15 minutes.
Whip the cream cheese and granulated sugar together in a large bowl until the texture is smooth and fluffy, about 3 to 4 minutes.
Gently fold in the fresh lemon juice and lemon zest just until blended, avoiding overmixing.
Pour the lemon filling over the chilled crust and even out the top with a spatula.
Refrigerate the tart for at least 6 hours or preferably overnight until it is fully set. Serve chilled.
