In a blender, crush the cookies into crumbs. Melt the butter in the microwave then mix with the mixed biscuits.
Pack the mixed biscuits in the bottom of a 20cm springform pan (I add a rhodoïd film first to facilitate the unmolding of the cheesecake). Press well with the back of a spoon or a glass. Refrigerate while waiting for the rest.
Cheesecake filling
Soften the gelatin in cold water.
In a container or in a food processor, whisk together the Philadelphia, mascarpone, vanilla and powdered sugar.
Separately, whip the whipping cream very firm too.
In a very small saucepan, heat the milk and melt the well-drained gelatin off the heat.
Place the whipped cream in the cream cheese mixture then whisk to evenly homogenize the texture. This filling should already hold together well.
Pour in the lukewarm milk and whisk again to obtain a homogeneous mixture.
Add the biscuits cut in 4 with a spatula. Place this filling in the mold, on the layer of packed biscuits. Smooth the top with a small spatula. Refrigerate overnight.
Chocolate topping
Heat the chocolate and cream in a bain-marie. Off the heat, add hot water: the chocolate becomes smooth and shiny. Let cool slightly (it must remain fluid).
Pour part of the topping into a small pastry bag and pipe drops of batter all around the cheesecake. For the top of the cheesecake, pour the topping in the center and smooth with a spatula over the entire surface. Refrigerate 10 minutes.
whipped cream decor
Whip the whipped cream with the icing sugar. Fill a pastry bag then pipe domes all around the cheesecake. Decorate with Oreo cookies cut in half. Add cookie crumbs (optional)
Keep refrigerated until tasting.
Notes
This no-bake cheesecake will keep for about 4-5 days in the refrigerator in a bell jar or airtight container.