Directions

1. Very lightly butter a 1-litre pudding basin. Heat oven to 180C/fan 160C/gas 4. Coarsely grate one of the apple quarters and thinly slice the rest. Combine the sliced apple and blackberries, toss with the 2 tbsp caster sugar and spoon half into the bottom of the basin.
2. Mix together the flour and baking powder. Beat both the sugars and butter together in a large bowl with an electric hand beater until light and creamy. Break in 1 egg and beat well, then beat in the second egg (the mix will look curdled). Sift half the flour mixture over the sponge mixture and fold in gently. Carefully stir in half the milk, then repeat with the rest of the flour and milk, followed by the orange zest and reserved grated apple.
3. Spoon two-thirds of the sponge mixture over the fruit mix in the basin and level off. Spread the rest of the fruit on top, followed by the remaining sponge mix. Place the basin in a small roasting tin half filled with hot water. Bake for 1 1/4 hrs (lay foil over the top for the last 15 mins if it is browning too quickly) until a skewer inserted in the middle comes out clean.
4. While the pudding is baking, make the custard. Mix the sugar, custard powder and cornflour with 1 tbsp of the milk to make a paste. Beat in the egg yolk. Pour the remaining milk into a pan, slit the vanilla pod lengthways and scrape in the vanilla seeds. Add the pod to the milk and bring just to the boil. Pour this over the cornflour mix, stir, then pour into a clean pan. Cook over a medium heat, stirring all the time, until it is thick enough to coat the back of a spoon. Remove from the heat and stir in the creme fraiche.
5. Loosen pudding from the sides of the basin with a round-bladed knife and carefully invert it onto a serving plate. Serve with the custard.