Using a mixing bowl with the paddle attachment, blend the cream cheese until it becomes smooth. Slowly add the sweetened condensed milk. Mix in the lemon juice and vanilla extract, and continue beating until the mixture is thoroughly combined.

Pour the filling into the chilled graham cracker crust, cover the cheesecake with plastic wrap, and refrigerate for 3 ½ to 4 hours, or until it sets. This recipe makes one spring-form pan or 10 small cheesecakes.