For the lemon and mixedberry curd

— 130g mixed berries, such as raspberries, strawberries and blackcurrants — 125g caster sugar

— 5 egg yolks — zest and juice of 2 unwaxed lemons

— 2 tbsp cornflour, sifted — 50g very cold butter, cubed

For the mascarpone buttercream

— 150g mascarpone, at room temperature

— 150g unsalted butter, very soft

— 600g icing sugar — fresh berries and crystallised rose petals, to decorate Preheat the oven to 200C/ 180C fan/gas mark 6 and line the bases of four 20cm cake tins with baking parchment.

To make the cake batter, beat the egg whites with an electric whisk until they form soft peaks, then add the sugar one tablespoon at a time while mixing, until it is all incorporated and you have a glossy meringue mix. Cover the bowl and refrigerate until needed.

In a separate bowl, beat together the coconut oil and butter. Combine the yogurt, milk and extracts, and add them gradually to the butter mixture while beating. Sift in the flour and add the rest of the dry ingredients, plus half a teaspoon of salt, then mix to combine. Add a third of the meringue and mix to loosen the batter, then carefully fold in the rest of the meringue.

Divide the batter between the four tins and bake in the middle of the oven for approximately 20 minutes, or until a skewer inserted into the centre of each cake comes out clean.

Allow the cakes to cool for 10 minutes in their tins before turning them on to a rack to cool completely.

Meanwhile, for the syrup, pour 240ml boiling water over the teabags in a small saucepan and leave to steep for five minutes. Remove the teabags, add the sugar and bring to a boil over a medium heat, stirring until the sugar has dissolved. Let the syrup cool completely before brushing it on the cooled sponges (you will have some syrup left over).

To make the curd, cook the berries with the sugar in a small saucepan over a low heat until the sugar has dissolved and the berries have collapsed and released their juices. Mash gently with a fork.

Whisk the egg yolks in a heatproof bowl. Add the lemon zest and juice, cornflour and berry mix. Combine well.

Place the bowl over a pan of boiling water, making sure that the water doesn’t touch the bowl. Stir continuously until the mixture thickens to a curd consistency. Remove from the heat, beat in the butter, then pass the curd through a fine mesh sieve to remove any seeds and zest. Refrigerate until needed.

For the buttercream, drain any liquid from the mascarpone, then whisk it thoroughly before adding the butter a little at a time, until incorporated. Add a large pinch of salt and the icing sugar, in two batches, and mix until smooth and fluffy. Chill until needed.

To assemble the cake, lay one sponge on a serving plate. Using a round-tipped piping bag, pipe a circle of buttercream 2-3cm wide around the edge of the sponge. Fill the gap in the middle with curd and lay on the second sponge.

Repeat the process of piping and filling until you reach the top layer. Decorate this with buttercream, fresh berries and crystallised rose petals.