Preheat the oven to 180°C/160°C fan/350°F/gas mark 4. Grease an approx 20 x 24 cm baking dish.
Peel, core and thickly slice the apples. Place them in a pan with the brown sugar, vanilla extract, lemon juice and water.
Bring up to a simmer and cook for a couple of minutes until the apples have softened slightly but still retain their shape. Taste and add more lemon juice or sugar as required.
Tip them into the greased baking dish and spread level. Set aside.
To make the sponge, sift together the flour, cornflour, baking powder and salt in a large bowl.
In a separate jug, whisk together the milk, yogurt, melted butter, oil, vinegar, sugar and vanilla extract until smooth.
Pour the wet ingredients into the dry and stir with a balloon whisk until no dry lumps remain.
Drizzle the batter over the apples and spread it level. Scatter over a handful of flaked almonds.
Bake the pudding for 25-30 minutes until a skewer inserted into the centre of the cake portion comes out clean. Serve warm with custard or ice cream.