In a larger mixing bowl combine Jell-O and boiling water, stirring until Jell-O is dissolved. Allow to sit at room temperature until completely cooled.
In a food processor, blend graham crackers into crumbs. Blend in melted butter and sugar.
Press graham cracker mixture evenly into the base of a 9x13 baking dish to form the crust.
In a large mixing bowl, blend cream cheese until light and fluffy. Stir in powdered sugar, whipped topping, lemon juice and vanilla, mixing well.
Spread mixture over graham cracker crust, ensuring the cream cheese filling is level and spread right to the edges of the pan. Cover and refrigerate until Jell-O is completely cooled.
Pour cooled Jell-O overtop of cheesecake mixture.
Refrigerate until firmly set, at least 4-6 hours or overnight.
Notes
Start with softened cream cheese for easier mixing.
Spread the cream cheese layer all the way to the edge to create clean layers.
Allow Jell-O to cool to room temperature before adding.
Store in the refrigerator up to 4 days, in a tightly covered container.