Carrot cake with maple frosting

Heat the oven to 200C/fan 180C/gas 6. Wrap the halved carrots and orange slices in a baking parchment parcel, sit in a roasting tin, then roast for about an hour until really tender.

Put the roasted carrots and two orange slices (not the ends, and discard any remaining slices) in a food processor or blender and whizz to a purée.

Turn the oven down to 160C/fan 140C/gas 3 and butter and line the base of a deep, round 20cm cake tin. Put the butter, sugar, treacle and syrup in a pan and heat until everything has melted. Cool. Grate the remaining 100g of carrot. Stir in the carrot purée, grated carrot, eggs, orange zest and milk, the flour, spices and bicarb. Scrape the mix into the tin and bake for 1 hour, or until a skewer comes out with crumbs clinging to it. Cool.

For the icing, put the butter in a big bowl and beat for about 5 minutes until pale and creamy. Sift in the icing sugar then add the maple syrup and juice and beat for 3-5 minutes until very fluffy.

Split the cake in three. If you want neatly piped filling, pipe the buttercream in dots using a round nozzle on the bottom 2 layers and chill for 20 minutes to stiffen the icing before sandwiching the cakes together. Otherwise, spread with buttercream then sandwich together. Spread the rest of the frosting on the top, and when ready to serve, drizzle a little maple syrup on top.