Preheat the oven to 180°C/350°F/gas 4. Peel and core the apples, then cut into 1cm chunks. Put into a bowl, sprinkle with the cinnamon and toss until combined. Drizzle over the maple syrup and set aside.

Put the oil, sugar, vanilla and lemon zest into a mixing bowl and whisk thoroughly with a wire hand whisk or an electric mixer. Lightly beat the eggs with a fork to break them up, then add to the bowl and whisk for a couple of minutes until the mixture looks thick and slightly mousse-like.

Stir in the nuts and the apple mixture using a large metal spoon. Sift the flour, baking powder, bicarbonate of soda and salt into the bowl and fold in – the mixture will be quite stiff.

Put the egg whites into another bowl and whisk until stiff peaks form. Fold into the apple mixture in 3 batches. Transfer the mixture to the prepared tin and spread evenly.

Bake for 30 to 35 minutes or until a good golden brown and a skewer inserted into the centre of the cake comes out clean. Transfer the tin to a wire rack. Run a round-bladed knife around the inside of the tin to loosen the sponge, then leave to cool before turning out.

To make the topping, beat the butter with the sugar and maple syrup until smooth and creamy. Beat in the cream cheese.

Spread evenly over the top of the cooled sponge. Leave in a cool spot to firm up, then cut into pieces. Store in an airtight container, in a cool spot, and eat within 4 days.