1. Preheat the oven to 150°C. Grease and line a 24 cm springform cake tin with baking paper,
2. Combine the crushed cookies and melted butter and line the base of the prepared cake tin.
3. Heat the custard and half of the milk together – do not allow to boil.
4. Make a paste with the castor sugar, cornflour, eggs and the rest of the milk. Mix very well and make sure there are no lumps.
5. Add the warm custard mixture to the egg mixture and stir quickly and very well to combine. Return to the saucepan and stir continuously until the custard is thick. Allow to come to a gently boil then remove from the heat.
6. Add the chocolate and mix well to incorporate completely.
7. Pour the custard into the crust and bake for 35 minutes.

TO SERVE:

1. Make a ganache by heating together the milk and chocolate on a very low heat in a saucepan or on a low power setting in a microwave. Stir until the chocolate is glossy and melted. DO NOT OVERHEAT.
2. Spoon the ganache over the cooled tart and top with fresh raspberries.
3. Dust lightly with cocoa powder.