Eve's Pudding - Slow Cooker

1. Lightly oil a 900ml (1 1/2 pint) overproof dish that will fit in the slow cookers cooking dish. Place an upturned saucer into the dish and pour around 1" (2.5cm) of cold water. Switch the slow cooker to high. 2. Peel, core and slice the apples and place a layer in the base of the prepared dish. Sprinkle over some of the blackberries, some lemon rind and a little demerara sugar. Continue to layer the apple and blackberries until all used. 3. Cream the butter and sugar together until light and fluffy. Beat in the vanilla essence and then the eggs, a little at a time. Add a spoonful of flour after each addition. Fold in the extra flour with a spatula or metal spoon and mix well. 4. Spread the sponge mixture over the top of the fruit and level with the back of a spoon. Cover tightly with a piece of oiled tin foil. Place the dish in the cooking dish and pour around sufficient boiling water to come halfway up the side of the dish. Cover with the lid and cook in the slow cooker for 4 to 6 hours, until well risen and golden brown. If it springs back when pressed with a finger, the sponge is cooked. Dust with icing sugar and serve on it's own or with custard.