Roast the almonds
Preheat the oven to 170°C, conventional or 160°C, fan forced. Line 2 trays with baking paper. On 1 tray scatter the raw almonds for the praline and on the 2nd tray, evenly scatter the flaked almonds for the almond rocher.
Toast the raw almonds for 10 minutes then remove from the oven. Toast the flaked almonds for 15 minutes or until the flaked almonds are dark golden, checking halfway through and giving the pan a shake to ensure they colour evenly. Once you are happy all the almonds are coloured nicely, remove from the oven and set aside to cool. Once cool, store the almonds in separate airtight containers until required.
Almond praline and paste
Line a tray with baking paper and set it aside. Place the roasted raw almonds and caster sugar in a frying pan or medium-based saucepan and toss together to combine, then place over medium heat. Shake the almonds occasionally and when you start to see the sugar turn glassy and melt around the outside, use a wooden spoon to gently stir the nuts every so often to distribute the melting sugar.
Continue to cook until all the sugar has dissolved and there is a golden caramelised coating on the almonds. Turn the heat off and scatter the almonds onto the prepared tray. If you can, separate the almonds by using the tip of your wooden spoon to flick them apart, so that you have individual almonds to decorate the top of the cake. Allow the praline to cool completely.
Once cooled, crush 80g of the praline into a paste using a small food processor or a pestle and mortar or place it in a plastic bag and smash using a rolling pin until as fine as possible. Choose the almonds that are clumped together and save the singular ones for the top decoration. Cut the remaining almonds in half lengthways using a very sharp knife and set aside to decorate the cake later. Store the praline and sliced almonds in separate airtight containers
Almond custard
In a medium bowl, weigh the sugar, cornflour, salt and cream. Add the egg yolks last and hand whisk to make a creamy paste. Stream the milk in then the vanilla and whisk well. Scrape the mix into a small saucepan.
Place the saucepan on a medium-high heat and hand whisk at a slow pace to allow the heat to suffuse through the mix. Work the small balloon whisk into the corners of the saucepan (where the custard thickens first). After around 3 minutes of whisking, the custard will start to look like a creamy liquid. Speed up the whisking now the custard will thicken fast. It will look lumpy but just whisk quickly and it will all come together into an evenly thick paste in another 1 minute. Keep whisking to achieve silky, evenly thick success.
As soon as it looks smooth and thick, slow down the whisking and wait for a few burp-like bubbles to pop over the surface. It's a super thick custard and your whisk should leave obvious furrows as it moves through the mix.Take the pan off the heat. Scrape the custard into a bowl and press a piece of plastic wrap on the surface of the custard to prevent a rubbery skin forming. Cool the custard in the fridge overnight or for a minimum of 4 hours.
French flourless chocolate sponge
Preheat the oven to 170°C, conventional or 150°C, fan forced. Grease and dust 2 x 20-cm cake tins with cocoa then line the bases with baking paper.
Place the egg yolks and half the icing sugar in the bowl of an electric mixer fitted with the whisk attachment and whip until pale and thick. Decant the sabayon into a larger bowl, so you can use the electric mixer bowl to whip the whites. Ensure the bowl is clean and dry and place the whites and salt in the bowl fitted with the whisk attachment, then whip on high speed until soft ribbons form. Reduce the speed to medium and gradually add the remaining icing sugar, 1-tablespoon at a time. Continue to whip the meringue until firm peaks form, but don't overbeat.
Using a spatula, fold the meringue into the sabayon one-third at a time, alternating with the cocoa, also one-third at a time. Sift the cocoa over the surface of the sabayon again before folding it through to prevent any lumps finding their way into the sponge. Meringue lumps may start to form as the meringue sits dormant in the stand mixer bowl. To prevent this, use a spatula to first smooth them over the surface of the sponge before actually folding them through. Trying to remove a lump of meringue from the sponge after it’s folded through will result in over-working the batter. If you can see lumps, use a whisk in a folding motion to remove them.
Pour the sponge into the prepared cake tins and smooth the surface gently with an offset palette knife. Bake for 15-18 minutes. (My sponges took 25 minutes) The sponge is ready when the middle bounces back when pressed with your finger. Remove the sponges from the oven and allow to cool in the tins.
Almond rocher
Preheat the oven to 170°C, conventional or 160°C, fan forced. Line the base and sides of 2 x 20-cm cake tins with baking paper.
Place the egg whites and salt in the bowl of an electric mixer fitted with the whisk attachment and whip on high speed until soft ribbons form, then reduce the speed to medium and gradually add the icing sugar, 1 tablespoon at a time, allowing a few seconds between each addition. Whisk the meringue for 5-7 minutes or until thick and glossy. Remove the bowl from the electric mixer. Roughly crush the toasted flaked almonds using your hands, then using a spatula fold through the meringue along with the vanilla paste until thoroughly combined. Divide the meringue between the prepared tins and bake for 30-45 minutes or until the top is crisp and golden. Remove the rochers from the oven and allow to cool in the tins.
Chocolate ganache
Place the chocolate in a bowl and have a whisk at-the-ready. Place the cream in a saucepan over medium heat and bring to the boil, then pour the cream over the chocolate. Set aside for 5 minutes for the chocolate to melt then whisk until smooth and glossy. Set the ganache aside at room temperature until you are ready to assemble the cake.
To assemble
Whisk the mascarpone until firmly whipped. Use a spatula to soften the almond custard, removing any lumps. If the lumps are persistent use a stick blender to smooth out the mixture. Using a spatula, fold the custard through the mascarpone in three batches. The aim here is to retain the thickness you have whipped into the mascarpone by adding the custard slowly. Once you have finished, you should have a thick filling that holds up firmly and will be spread over the cakes, not poured over them. If the finished almond custard is not as thick as you had hoped, return the entire filling to the stand mixer and whisk on medium speed until firm.
