Sweetness and light sourness… A soft sponge biscuit and a crunchy layer… The play on contrasts and combinations always creates a lot of impressions. Imagine that all the laws and rules have no power over you, and cook as your soul requires, getting the most out of the cake!
- Cut the butter into small cubes and put it in the freezer.
- Pour the juice into a saucepan and boil it over a medium heat, stirring occasionally, to the 90 ml (3.05 fl oz) volume. Add the lime juice, and cool.
- Prepare a water bath by bringing the water to a boil over a medium heat.
- Mix the yolks and sugar in a heat-proof bowl and whip them on a medium speed for a minute. Pour the cooled juice into the yolk mixture. Place the bowl in a water bath, and cook until the curd thickens and completely envelops the spoon, occasionally stirring (for around 20 minutes).
- Add the zest to the mass a couple of minutes before it’s ready, and mix well. When the mixture thickens and becomes dense, remove it from the bath and grind through a sieve into a tall glass.
- Mush the mass with a submersible blender, adding 2-3 pieces of cold butter at a time, making sure that it is completely dispersed in the curd.
- Pour the curd into a hermetically sealed jar, and it store in the fridge.
You better cook the curd in advance (one day before use).
Chocolate sponge biscuit
- Divide the eggs into whites and yolks and leave them for 25 to 30 minutes at the room temperature.
- Mix the flour with the baking powder and cocoa, and sift.
- Divide the sugar into 2 parts: 100g (3.55 oz) and 25g (0.85 oz). Whisk the yolks with sugar (100g | 3.55 oz) and vanilla extract in a deep bowl, whip until fluffy and lightened (for 3 minutes). Add the flour mixture and knead the dough with a spatula until smooth.
- In a separate bowl, whip the egg whites until fluffy, smooth foam; add the sugar (25g | 0.85 oz) and whip until stable dense peaks.. Add one third of the meringue to a bowl of yolks and whip it with a mixer on a slow speed until smooth. Gently pour the resulting mass into a bowl with the remaining meringue, and knead the dough with wide circular movements, using a spatula.
- Preheat the oven to 200C (392F). Cover the baking sheet (30x40 cm) with parchment. Spread the dough evenly over the baking sheet. Smooth and lightly hit the work surface several times. Bake the sponge biscuit for 10 to 12 minutes. The perfect biscuit should not stick to your hands!
- Remove the sponge from the oven and cool. Then pour the surface of the biscuit with the cocoa, using a sieve. Cover the biscuit with a new sheet of parchment and turn it over. Remove the bottom sheet of parchment and leave at the room temperature until assembling. Take a 16 cm (6.3 inch) diameter culinary ring to cut three equal circles.
- Bring the egg whites to the room temperature. Melt the chocolate and coolit. Sift the cocoa and the cornstarch together in a small bowl. Add a pinch of salt.
- Pour the egg whites into a dry mixer bowl, pre-wiped with the vinegar. Start whipping on a medium speed until a fluffy foam, consisting of many small bubbles.
- Start adding sugar, 1 tablespoon at a time, without increasing the speed, whisking after each addition for at least 15 to 20 seconds. When all the sugar is in, you should increase the speed to maximum and whip for another minute.
- Turn off the mixer, and add the cocoa mixture and the lime juice. Whisk. At the very end, add the chocolate, and the bring the meringue to an absolutely smooth state, at the lowest mixer speed.
- Preheat the oven to 180C (356F). Cover the baking sheet with the parchment paper. Place the meringue on the paper and smooth. Bake it for 25 minutes without opening the oven door! Cool down. Cut the two circles (diameter = 16 cm | 6.3 inch) with the same ring. You better store the meringue in the cold before assembling the cake.
- All the components must be cold! Mix the mascarpone and the cream in a deep bowl. Start whipping the mass at a low speed, gradually increasing it.
- As the custard becomes dense, turn off the mixer and add the curd to the custard; gently stir it with a spatula until smooth.
- Start assembling immediately! Dry the berries well with a paper towel (especially if you cut them!).
- Chocolate sponge cake layer - 160g (5.60 oz) of custard - berries - meringue layer - 160g (5.60 oz) of custard - berries. Repeat the order one more time and finish with the chocolate crust.
- Spread the remaining cream evenly over the sides and the top of the cake. Align the cake, and store it in the cold. You can also add 1 tablespoon of the pure curd between each layer of cream and the biscuits, but keep in mind that due to its consistency, it will flow out a little when the cake is cut.
- Chop the crumbs from the chocolate sponge biscuit into crumbs, and dry them. Sprinkle the finished cake after 8-12 hours in the cold. As an alternative, you can cover the cake with the curd.
Decorate the cake at your discretion.