Crush Oreos in food processor and add melted butter and sugar.
Press mixture into bottom and partway up sides of springform pan.
Refrigerate at least 30 minutes to firm.
Beat cream cheese, lemon juice and sugar until well mixed. Set aside.
In another bowl, add 1 cup of boiling water to gelatin and stir to dissolve.
Set aside to cool.
Whip heavy cream and powered sugar until stiff peaks form.
Once gelatin has began to thicken, fold into whipped cream and stir until blended.
Fold and blend cream cheese mixture into whipped cream mixture.
Pour/spread into pan and garnish with lemon zest.
Refrigerate for at least 4 hours or until firm.
You can also garnish with crushed cookies if desired.