Crush graham crackers: Put graham crackers in a large resealable plastic bag, and crush them with a rolling pin until very fine crumbs form.
STEP 2
Mix crumbs: Pour crumbs into a medium bowl; stir in sugar. Add melted butter and stir until well combined.
STEP 3
Press crust: Press the crumb mixture into a 9-inch springform pan, spreading it 1 1/2 to 2 inches up the side; press flat. Chill crust in freezer for 10 minutes.
STEP 4
Make filling: Using an electric mixer set at medium-high speed, beat the cream cheese until smooth. Beat in condensed milk gradually, scraping the sides of the bowl. Add lemon juice and vanilla, mixing well.
STEP 5
Assemble: Pour the filling into the chilled crust; smooth the top with a rubber spatula. Cover with plastic wrap, and refrigerate until firm, 2 1/2 to 3 hours.
STEP 6
Serve: Unclasp sides of the pan, and remove cheesecake.