Apple, parsnip & brown butter traybake

1. Preheat the oven to 180°C, gas mark 4. Line a 25x18cm baking tray with baking parchment. Put all the cake ingredients in a large bowl with a pinch of salt, and beat together until smooth. Pour into the tray and smooth the top, then bake for 35-45 minutes until risen and just firm, and a skewer inserted into the centre of the cake comes out clean. Cool in the tin for 10 minutes, then turn out onto a wire rack to cool completely.

2. To make the brown butter, melt the butter in a small pan and let it bubble gently until it turns golden brown and smells nutty. Strain into a small bowl, leaving the white solids behind, and leave to solidify. Once cold, it can be put in the fridge to speed up setting, but take care not to leave it there too long as it will set too hard.

3. For the apple crisps, preheat the oven to 200°C, gas mark 6. Line a large baking tray with baking parchment. Slice the apple very thinly and spread over the tray in a single layer. Remove any pips, brush with lemon juice, then with melted butter, and sprinkle over the sugar. Bake for 10-12 minutes and leave to cool. Don’t make them too far in advance or they will go soft.

4. For the buttercream, tip the icing sugar into the bowl of a freestanding mixer. Add the lemon juice and brown butter and beat well until smooth and fluffy. Spread over the cooled cake and decorate with apple crisps.

Cook’s tip 

Brown butter adds a delicious nutty flavour to the icing. If you like, leave the toasted milk solids in for a stronger flavour, or stir into the cake mixture.