Carrot cake

For the cake: preheat the oven to 180C/gas 4. Grease and line one deep or two shallow 20cm cake tins.

Sift the flour and baking powder into a large bowl and mix in the cinnamon, cloves and nutmeg.

In a separate bowl, use an electric mixer to whisk together the muscovado sugar, sunflower oil and eggs until smooth.

With a large metal spoon, fold in the carrots and walnuts, then fold in the flour and spice mixture until well combined.

Spoon the mixture into the prepared cake tin(s), place on baking trays and bake until the cake is golden-brown and a skewer inserted into the centre comes out clean (test after 25 minutes if you are using two shallow cake tins; 40 minutes if using a deep cake tin). Remove from the oven and leave to cool in the tin(s) on a wire rack.

For the frosting: pare a few shreds of lime zest with a zester and set aside to use as decoration. Finely grate the remaining lime zest and squeeze the juice from one half of the fruit.

Beat the mascarpone in a bowl with the softened butter, icing (or light muscovado) sugar and finely grated lime zest. Add the lemon juice slowly, beating the mixture continuously to prevent it from curdling. You may not need to add all of the lemon juice; add to taste.

If you have made one deep cake, cut it horizontally into two layers. Sandwich them (or the small cakes) together with some of the mascarpone mixture. Spread the frosting over the top and smooth it down the sides to cover completely, then ruffle the surface.

Either refrigerate and serve chilled, or serve immediately, topped with the reserved strips of lime zest.