To prepare the Oreo cookie base place the cookies into a plastic bag and bash them with a rolling pin until they are fine crumbs. Alternatively, process in a food processor or blender until they reach the right consistency.
Stir in the melted butter until well combined and press into the base of an 8 inch round silicone cake tin with a depth of 3 inches. Place in the refrigerator to set while you get on with the ice cream.
Weigh the bowl you're going to make your ice cream in.
To prepare the no churn ice cream, whip the double cream with a whisk until it becomes soft and pillowy and begins to hold its shape.
Pour in the sweetened condensed milk and stir until combined.
Weigh the bowl again, subtract the weight of the bowl and this is the weight of how much ice cream mixture you have. Divide this mixture into three separate bowls. Place two of them in the fridge.
Sift the cocoa powder into the first bowl and whisk until thick and well combined. Spoon this mixture over the Oreo cookie base and level with the back of a spoon. Pop into the freezer for 20 minutes.
Meanwhile, cut one of your mini Cadbury creme eggs in half so you can see the shade of orange the 'yolk' is. Add enough orange food colouring, a few drops at a time, whisking after each addition, until you reach the desired shade.
Spoon this orange coloured ice cream over the chocolate ice cream, smooth with the back of a spoon and pop back into the freezer for 20 minutes.
Add the vanilla to the remaining bowl of ice cream mixture, stir well and spoon over the orange ice cream layer. Leave for several hours to chill entirely, preferably overnight.
Just before you want to serve your ice cream cake, melt the milk chocolate in a heatproof bowl suspended over a pan of barely simmering water.
Turn the silicone cake pan with your ice cream cake in it upside down and carefully roll down the edges of the cake tin to release the ice cream cake. Transfer right side up to a cake stand.
Drizzle the melted milk chocolate around the outside top edge, allowing a little bit to drip down the sides.
Drizzle some of the remaining milk chocolate in the centre of the ice cream cake so that there is enough melted chocolate there to hold a large Cadbury creme egg upright in the centre.
Cut the remaining mini Cadbury creme eggs into half and arrange around the outside top edge of the ice cream cake, and place the large Cadbury creme egg in the centre.
You can store the ice cream cake in the freezer until needed, without the Cadbury creme egg decorations (these freeze so that they are rock solid!). You can simply cut one slice at a time, leaving it to defrost 5-10 minutes to reach a softer consistency, or allow the whole cake to stand at room temperature for about 20 - 30 minutes before serving (if you can wait that long!)