Courgette, lemon and mascarpone cake

Recipes are rarely unique to the writer. They have a provenance in the cultures and the people that we encounter. My recipes develop organically as I find inspiration around me. Perhaps I will adapt a method suggested in a cookbook with a flavour combination found via a friend, a food writer or a famous chef. 

This cake is a fantastic example of the complementary process of recipe development: a sponge adapted from Nigella comes together with a lemon curd from Nigel and mascarpone icing from Mary, with decorative pieces modified from BBC Good Food. Separately, each of these elements are good in their own right (I would eat the lemon curd straight from the jar). Together, though, they make the most glorious summertime cake.

The light, syrup-soaked sponge reveals rather beautiful green speckles when it is sliced. Don’t be put off by the vegetables - courgette and cake make wonderful bedfellows. You can’t taste the courgettes, but they add moisture and a delicate sweetness. I’ve added just a little sugar to the mascarpone icing, so it is not too heavy and balances the richness of the luscious, sharp-sweet curd. To take a bite of this cake is, for me, to taste sunshine. 

You can make most elements of this cake ahead. The lemon curd can be made up to a week or two in advance; the meringues, lemon slices, icing and even the sponge can be made the day before eating. On the day, you can just assemble, decorate and serve with fresh summer berries. If there's any leftover after the first (and second) helping, store in the fridge because the icing and curd can run in the heat.

Courgette, lemon and mascarpone cake (1)

 

Ingredients

Lemon curd

  • Zest and juice of 2 unwaxed lemons
  • 100g caster sugar
  • 50g butter, cut into cubes
  • 2 eggs

Mini meringues (optional)

  • 1 large egg white
  • 30g caster sugar
  • 25g icing sugar

Candied lemon

  • 100g golden or plain caster sugar
  • 1 unwaxed lemon, thinly sliced into rounds

Courgette sponge

  • 250g courgettes (1 large courgette), weighed before grating
  • 2 large eggs
  • 125ml vegetable oil
  • 150g caster sugar
  • 225g self-raising flour
  • 1/2 tsp baking powder
  • 1/2 tsp bicarbonate of soda

Mascarpone icing

  • 250g mascarpone cheese
  • 1-2 tsp vanilla extract
  • 3 tbsp icing sugar, sifted
  • Fresh berries, to decorate and serve

 

Method

Lemon curd (can be made in advance)

  1. Put the lemon zest and juice, sugar and cubes of butter into a heatproof bowl set over a pan of simmering water - make sure the bottom of the bowl doesn’t touch the water. Stir with a whisk until the butter has melted. 
  2. Beat the eggs lightly with a fork then stir into the lemon mixture. Let the curd cook, stirring regularly, for ten minutes, until it is thick and feels heavy on the whisk. Remove from the heat and stir occasionally as it cools.
  3. If it develops some lumps from the cooked egg white, you can strain through a sieve. Pour into sterilised jars and seal. If will keep for a couple of weeks in the fridge, but I never find lemon curd lasts that long!

Mini-meringues (optional)

  1. Preheat the oven to 100°C. Line a baking tray with non-stick baking parchment.
  2. Beat the egg white in a clean mixing bowl with an electric whisk until the mixture stands up in stiff peaks. Turn up the speed and add the caster sugar a little at a time, beating well after each addition. The mixture should look thick and glossy.
  3. Sift the icing sugar over the mixture and fold in with a big metal spoon. 
  4. With two teaspoons, scoop up a heap of mixture with one spoon and use the other to ease a small swirl onto the baking sheet. Repeat until all the mixture has been used up.
  5. Bake for 1-1  1⁄2 hours until the meringues are a pale golden colour and crisp underneath. 

Candied lemon and lemon syrup

  1. Place the sugar and water in a saucepan and heat gently to dissolve the sugar. Bring the syrup to the boil, drop in the lemon slices and simmer for 15 minutes.
  2. Carefully remove the slices from the syrup and place on a piece of baking parchment to dry. They will remain a little sticky, so if you want them to dry fully, place them on a tray lined with baking parchment and bake in the oven at a low heat (around 40-50°C) for 30 minutes.
  3. Set aside the remaining syrup.

Sponge cake

  1. Preheat the oven to 180°C.
  2. Wipe the courgettes with a kitchen towel (don’t peel them) and grate using the course side of a box grater. If you grate them too finely, they will turn to mush. Place them in a sieve over the sink to let any excess water drain.
  3. Put the eggs, oil and sugar in a large bowl and beat until creamy. Sieve in the flour, bicarbonate of soda and baking powder and continue to beat until well combined. Fold in the grated courgette with a large metal spoon.
  4. Pour the mixture into the tins and bake for 30 minutes, checking after 20-25 minutes. They should be golden brown and firm to the touch - a skewer inserted into the centre should come out clean. Leave to cool for 5 minutes, then turn out on a cooling rack.  
  5. Whilst the cakes are still warm, lightly pierce the top of each sponge with a fork and brush over a few spoonfuls of the lemon syrup. Leave to cool.

Mascarpone icing

  1. While the cakes are cooling, make your mascarpone icing. Beat the mascarpone in a small bowl with the sieved icing sugar and the vanilla extract, until the sugar is just incorporated and the icing is thick. Be careful not to beat too much, or the mixture may split. 

Assembly

  1. To assemble, spread half of the mascarpone icing on one sponge and decorate with your mini meringues, lemon slices and fresh berries. Fresh flowers are also nice for decoration, but make sure you check first which ones are safe to use. 
  2. Put the other sponge on a plate and spread with the remaining mascarpone icing, followed by a layer of lemon curd. Gently lift up the first sponge and place on top. 
  3. Serve with leftover berries and a big smile.

 

Courgette, lemon and mascarpone cake (2)
Courgette, lemon and mascarpone cake (3)