Combine graham cracker crumbs and 1/4 cup granulated sugar in a bowl. Pour in melted butter and mix until the crumbs are evenly moistened.
Press the crumb mixture firmly into the bottom and slightly up the sides of a 9-inch pie plate. Place the crust in the freezer while you prepare the filling.
In a small bowl, sprinkle the gelatin over the cold water. Let it sit for 5 minutes to bloom.
In a large bowl, beat the softened cream cheese until smooth. Gradually beat in the powdered sugar and vanilla extract until fully combined.
Beat in the lemon juice.
In a separate, clean bowl, whip the cold heavy whipping cream until stiff peaks form. Set aside.
Gently heat the bloomed gelatin mixture in the microwave for about 10 seconds until it is completely liquid and clear. Do not boil.
Slowly pour the liquid gelatin into the cream cheese mixture while mixing on low speed. Mix until just combined.
Gently fold the whipped cream into the cream cheese mixture until no streaks remain.
Pour the filling into the chilled crust. Smooth the top with a spatula.
Cover the cheesecake loosely with plastic wrap and refrigerate for at least 6 hours, or preferably overnight, until firm.
Before serving, top with fruit pie filling or fresh berries if desired.
Notes
For a firmer set, you can add 1/4 cup of sweetened condensed milk along with the powdered sugar.
If you do not have graham crackers, vanilla wafers or shortbread cookies work well for the crust.
Chill time is necessary for the gelatin to set the filling properly.