Remove the tops of the Oreos and scrape off the white cream into a bowl with the help of a knife. Crumble the "naked" cookies with a rolling pin and a resealable freezer bag. Set aside a third of the cookie crumbs for later.
Add the melted butter to the remaining two-thirds of the cookie crumbs and mix with a spoon. Then press the crumb mixture to the bottom of a springform pan.
Add the cream cheese, Oreo cream, sugar, milk, and vanilla extract to a saucepan and heat the mixture over medium low heat, stirring until smooth.
In the meantime, soften the gelatin in a small bowl of cold water. When pliable, remove any excess water, add the softened sheets to the cream mixture and stir until completely dissolved.
Pour the cream mixture onto the Oreo crust, give the springform a gentle shake to smooth the surface of the cream, and then cover gently with the remaining cookie crumbs. Garnish as desired with slices of mango, raspberries, and mint leaves. Refrigerate for 4 hours until firm.