Put the graham crackers in a resealable plastic bag.
Crush the crackers with a rolling pin until fine crumbles.
Transfer the crumbles into a small bowl and pour over the melted butter.Stir until well combined.Press the crumble mixture into the bottom of pan and refrigerate while making a filling.
Combine the gelatine and water in a small bowl and sit until the gelatine is absorbed (about 5-10minutes.)
Place the 100g of heavy cream in a small sauce pan. Bring to a simmer over medium heat.Add the gelatine mixture, and stir until the gelatine has completely dissolved. Set aside.
Beat the cream cheese and sugar in a medium bowl until smooth.Add the yogurt, lemon juice, and remaining heavy cream and beat until combined. Add the gelatine and heavy cream mixture and beat until combined.
Pour the filling into the crust. Smooth the top with a spatula and refrigerate until firm.
Optional: Decorate with whipped cream and/or frozen berries.