Sponge:

• Melt the chocolate and butter in a small saucepan over a low heat, stirring from time to time. When the mixture is smooth, turn off the heat and set aside to cool.
• Put the 3 eggs and the sugar in a mixer bowl and mix for 10 minutes until they triple in volume.
• Combine the flour with the starch and then fold the mixture into the egg cream. Incorporate it slowly, with upward movements. Do the same with the melted chocolate.
• Mix the egg whites in another bowl until you get a firm foam. Incorporate the egg whites into the mixture with gentle upward movements.
• Preheat the oven to 180 °C ( 356 °F) and line a 25/35 cm (10x14 inches) baking tray with parchment paper.
• Coarsely chop the walnuts. Add them to the mixture, stirring gently. Pour the mixture into the tray and level it.
• Bake for 20-23 minutes, until it passes the toothpick test.
• Remove the tray from the oven and flip the cake over onto a wire rack. Remove the parchment paper and leave the cake to cool.

Chocolate cremeux:

• Crush the tonka beans in a mortar and pestle. Coarsely chop the chocolate and put it in a bowl with the finely ground tonka.
• Mix the egg yolks with the sugar until lightly whitened.
• Place the cream and milk over a low heat in a double-bottomed saucepan. When the milk is hot, pour it gradually over the yolks. Mix well. Put the mixture back into the pan and cook for about 10 minutes, stirring gently, until it thickens. The cream should not boil.
• When the cream is ready, pour it over the chocolate and stir well.
• Cut the cake into a 20/30 cm ( 8x12 inches) rectangle and transfer it to a removable mold of the same size.
• Pour the cream on top and spread it over smoothly. Cover the pan with cling film and refrigerate.

Peach mousse:

• Boil the water with 50 grams (1/3 cup) of sugar and a vanilla pod split in two.
• Remove the pits from the peaches, add them to the water and boil for 10 minutes, then turn off the heat and cover the pot.
• Cut 300 grams (1 1/4 cup) of peaches into chunks. Add a drizzle of lemon juice and blend them. Once you have a fine peach purée, strain it through a fine sieve.
• Set aside 100 grams ( 2/3 cup) of the purée for the jelly. Heat up the remaining purée along with the grated ginger.
• Hydrate the gelatin sheets in cold water. After 5 minutes, add it to the peach purée. Mix well.
• Next, add the vanilla and Greek yogurt and mix until fully incorporated. Refrigerate.
• When the peach cream begins to thicken in the refrigerator, add the powdered sugar to the whipping cream and mix until it becomes firm. Then incorporate it into the peach cream.
• Pour 2/3 of the mixture over the cake and place the cake in the refrigerator.
• From the acetate sheet make 2 rolls, 30 cm (12 inches) long and 1.5 cm (1/2 inches) in diameter.
• Put the remaining mousse in a piping bag and fill the two rolls. Close the ends with foil and slide them into the freezer.

Peach jelly:

• Place the water, sugar, and glucose over a medium heat. Boil for 6 minutes, timed from when it beings to boil, to slightly reduce the liquid.
• Strain the peach purée and mix it with the syrup.
• Hydrate the gelatin in cold water. After 5 minutes, add it to the peach juice. Mix well and leave to cool.
• Cut out 6 rectangles of acetate foil of 7/5 cm (3x2 inches) and spread the cooled jelly over the top.
• Remove the mousse rolls from the freezer. Peel off the foil and quickly cut them into 7 cm (3 in) pieces. Roll each piece of mousse in the jelly-covered foil. Secure the rolls with tape and return them to the freezer.

Chocolate mousse:

• Melt the chocolate in a bain-marie, then leave it to cool, making sure it doesn't harden.
• Mix the sugar and whipping cream until you get a firm whipped cream. Incorporate it into the cooled chocolate with upward movements. Put the cream in the piping bag.
• Cut the cake into 6 pieces. Decorate each piece with chocolate cream and slide them back into the refrigerator.

Decoration:

• Put two-thirds of the chocolate in the bain-marie and leave until it has melted, around 60 °C (140 °F). Add the rest of the chocolate and stir well to melt and reduce the temperature to 40 °C (104 °F). Turn off the heat. The chocolate is now ready to use.
• Cut one 16x14 cm rectangle and six 7x14 cm (3x6 inches) rectangles from the acetate sheet. Cover the large rectangle with chocolate, spreading it evenly and set aside.
• On the small rectangles, make 7 or 8 chocolate lines, lengthwise. On the short edges (7 cm/ 3 in), draw smaller lines, one on each edge. Then, join the short edges so that the lines are on the inside. Leave the chocolate circles to cool. Follow the procedure shown in the pictures.
• Cut the large sheet of chocolate into rectangles of 2x7 cm (1x3 inches), using a thin knife. Clean the blade after each cut. Put the rectangles in the refrigerator.

Assembly:

• Arrange two chocolate rectangles on each piece of cake, positioning them diagonally.
• Gently peel off the acetate foil around the chocolate spiral and transfer it to the top of the cake.
• Remove a peach mousse roll from the freezer. Peel off the foil and position it in the center of the chocolate spiral. Repeat this step with the remaining 5 pieces.
• Now the cake is ready! Full of flavors, textures, layers, but especially chocolate... waiting for you to taste it.

Enjoy!