Start by making the crust. Add the Oreos to a food bag and bash into fine crumbs with a rolling pin, or add them to a food processor and process until you have fine crumbs. Then, in a large bowl, mix the oreo crumbs with melted butter, and mix till you have the texture of wet sand and all the crumbs are moistened.
Lightly grease and line the bottom of a 8-inch or 9-inch springform or loose bottom pan with parchment paper. Scoop the mixture into the pan, and firmly press it down, using a glass or measuring cup, until you have one even layer.
Then freeze the base for 10 - 20 minutes, while you make the cheesecake filling.
To make the filling: Using a stand mixer fitted with the whisk attachment, or in a large mixing bowl using a handheld mixer, beat room temperature cream cheese until smooth.
Next, add in the icing sugar, caster sugar, salt and vanilla extract and mix until well combined.
In a separate bowl, pour in the double cream / heavy cream and whisk until, cream thickens and stiff peaks form.
Add ⅓ of the whipped cream and fold gently into the cream cheese mixture. Then, add in the rest of the cream and continue to fold gently, until everything is fully combined.
Then, add in the melted white chocolate and fold gently, until well mixed, and add in the chopped oreos and fold one last time.
Remove the base from the freeze, pour the cheesecake filling onto the crust, and carefully spread it around into one even layer. Place in the fridge for 2 hrs.
To make the ganache topping: In a microwave safe bowl, break up the milk chocolate and pour in the double cream / heavy cream. Microwave in 30 second increments, until fully melted, stirring in between each increment. Allow to cool to room temp.
Pour the ganache over the cheesecake and spread evenly. Then, cover tightly and place back in the fridge to set for at least 4 to 6 hours or overnight.
Once set, run a sharp knife around the edge of the cheesecake to release it out of the pan. Decorate with extra whipped cream and mini oreos, or however you wish to decorate. Then slice and enjoy!