Mix graham cracker crumbs, melted butter, and some sugar until evenly moistened.
Press the crust firmly into a pie plate.
Beat softened cream cheese until smooth.
Add pumpkin puree, sugar, pumpkin pie spice, and vanilla. Mix until smooth.
Fold in Cool Whip gently until combined.
Spread filling into the prepared crust.
Cover and refrigerate at least 2 to 3 hours, preferably overnight.
Top with whipped topping before serving if desired.
Notes
Use room-temperature cream cheese so the filling is smooth. Use plain canned pumpkin, not pumpkin pie filling. Press the crust firmly with a measuring cup so it holds together. Refrigerate at least 2 hours before slicing. Freeze without whipped topping if making farther ahead.
Keyword no bake pumpkin pie, pumpkin no bake dessert