Black bottom pie

Whizz the Oreos to crumbs in a food processor, then add the melted butter and briefly whizz again. Press into a 23cm springform cake tin, cover and chill.

Gently bring the milk to a boil in a heavy-based saucepan. Meanwhile, whisk the egg yolks and half the caster sugar together in a large, heatproof bowl until paler in colour, then whisk in the cornflour and salt. Whisk as you pour the hot milk onto the yolks, then return to the pan and cook over a low heat, stirring, until the mixture coats the back of a wooden spoon. Take off the heat and pour half into a bowl, while this is cooling soak the gelatine in cold water until pliable. Squeeze the water out of 2 of the leaves. Stir the chocolate and these gelatine leaves into the pan with the custard mixture until they have melted, then pour onto the base. Chill.

Stir the rum, vanilla, nutmeg and remaining 4 gelatine leaves into the warm, reserved custard mixture and leave to cool completely.

Beat the egg whites to soft peaks, then add the remaining caster sugar and beat until the mixture is stiff and glossy. Fold this into the cooled custard, then spoon on top of the chocolate custard and chill until set – about 4 hours. Whip the cream and icing sugar to soft peaks, spoon on top of the pie, then shave a little chocolate over the top to serve.