For the topping:
75g soft light brown sugar
3 tablespoons double cream
85g hazelnuts, roughly crushed
½ Pink Lady apple, cored and sliced into thin wedges
1. Pre-heat the oven to 180ºC/Gas Mark 4. Lightly grease a square loose-bottomed 20x20cm cake tin and fully line with baking parchment.
2. Finely grind the hazelnuts in a mini processor. Put the butter and sugar in a bowl and cream together with a wooden spoon. Whisk in the eggs and yoghurt until fluffy. Sift the flour and baking powder together and fold in with the ground hazelnuts.
3. Fold in the sliced apples and spread the mixture evenly into the tin. Sift over the icing sugar then put the tin on a baking tray and cook for 1 hour.
4. Meanwhile, prepare the topping. Put the butter, sugar and cream into a small pan and melt together. Stir in the nuts and fold in the apple.
5. Spread the mixture over the cake when it has cooked and put back in the oven to bake for a further 10-15 minutes.
6. Put the tin on a wire rack to cool slightly, then lift out the cake whilst stlll warm.
Recipe courtesy of www.pinkladyapples.co.uk