1. Lightly oil a 900ml (1 1/2 pint) pudding basin and line the base with a small circle of non-stick baking parchment. Place an upturned saucer into the slow cooker cooking dish and pour around 2.5cm (1") of cold water. Switch the slow cooker to high. 2. Cream the sugar and butter together in a large bowl until fluffy and light. Add the beaten eggs a little at a time, adding 1 tablespoon of flour after each addition. When all the egg has been added, stir in the remaining flour. 3. Add the grated chocolate and mix in lightly, then stir in the milk, dates and hazelnuts. Stir lightly until well mixed together. 4. Spoon the mixture into the prepared pudding basin and level the top. Cover with a double sheet of tin foil with a central pleat. Secure with string or by scrunching the tin foil around the rim of the basin. Place in the cooking dish and pour around enough boiling water to come halfway up the side of the basin. 5. Cook in the slow cooker for 4 to 6 hours, until the top feels firm. Carefully remove and allow to cool for 10 minutes before turning out on to a serving plate and sprinkling the top with chopped hazelnuts. 6. To prepare the sauce, heat the butter, sugar and chocolate together in a saucepan and heat until melted. Stir in the cream and brandy, then simmer for 3 minutes until thickened. Pour over the pudding and serve.