Preheat the oven to 175°C. Separate the egg yolks from the whites, keeping the yolks ready in a small bowl. Whip the whites in a stand mixer with the whisk attachment until stiff, then transfer them to the large bowl you'll use for the batter.

Put the yolks in the stand mixer bowl – I don't even bother washing out the bowl used for the whites, no need. Add the sugar to the yolks and start whisking. Gradually pour in 18 tablespoons of hot water. Keep whisking until the sugar has completely dissolved and you're left with a wonderful, sweet egg yolk cream.

You now have the whipped egg whites in the large bowl. Alternate between adding the flour-cocoa mixture and the yolk cream. Fold gently so you don't knock too much air out of the whites.

Divide the sponge batter evenly between the three prepared tins – the saucepans, which you've greased and dusted beforehand. All three should fit on the same oven rack side by side. Bake for about 45 minutes.

Don't open the oven for the first half hour, or the sponge may sink. After that, you can check if it's done. The centre should feel firm to the touch. Confirm by inserting a skewer into the middle – if it comes out clean, it's ready.

Take all three tins – saucepans out and set them on a wire rack to cool completely. Once fully cooled, turn the sponges out.

In a small saucepan, bring 300 ml of whipping cream to the boil. Remove from the heat and add 90 g of Willie's Cacao Venezuelan Black Carenero, roughly chopped beforehand. 90 g is one of the two bars you'll find in the pack.

Let the chocolate sit in the hot cream for about five minutes, then stir with a whisk. In the stand mixer fitted with the whisk attachment, beat together the butter and icing sugar. Add the chocolate mixture a spoonful at a time.

Once everything is well combined, start adding the mascarpone, about half a tub at a time, whisking thoroughly after each addition. Work through the full 1 kg of mascarpone this way.

Give the finished whipped cream a good, thorough stir with a large wooden spoon so it's not too airy – this helps stop the cake layers from sliding apart.

Bring another 100 g of cream to the boil. Add 90 g of chopped Willie's Cacao Venezuelan Black Carenero.

Let it sit for five minutes, then stir with a whisk. Gradually add the sour cream, stirring it into the chocolate mixture. The finished cream will be a little darker than the mascarpone cream. Use it to fill one or two of the cake's layers.

Your creams are ready – chill them in the fridge for an hour. Now slice the sponges: you have three baked sponge cakes in total. Cut each one into two, so you end up with three layers from each sponge. Spread raspberry jam over each layer.

The bottom of the cake will be the sponge from the 19 cm saucepan. Start with the darker sour cream chocolate mixture to join the first two layers together. Depending on how much cream you use, you might even manage to join the second and third layers too.

If the darker cream runs out, use a little of the mascarpone cream as well. Smooth the sides – they don't need to be perfectly finished yet, just filled in enough so there are no gaps or holes. Chill this first assembled sponge in the fridge.

Continue with the other two sliced sponges, now using the mascarpone cream. Portion it out so you'll still have enough left to coat the whole cake once it's assembled. Fill each sponge with cream and smooth the edges so the sides are even.

Chill everything in the fridge, ideally for three to four hours, or even overnight.

Now stack all the sponges on top of each other, with the 19 cm one at the bottom, of course. Secure the layers with wooden cake dowels, trimmed so they're completely hidden inside the cake. Then coat the whole cake, sides and top, with the remaining cream.

I finished mine by running a fork up and down the sides and around the whole cake to create lines – I set the cake on a turntable and turned it while dragging the fork around to get an even pattern. Chill the cake in the fridge for an hour before moving on to the finishing touches.

Bring 100 g of cream to the boil. Break in the Willie's Cacao Rio Caribe Gold chocolate and let it sit for five minutes, then stir with a whisk to make a smooth chocolate ganache. Let it cool. Once cooled, spread it over the sides of the cake to fill in the fork lines in the cream.

Smooth the ganache neatly, then arrange the raspberry pralines on top of the cake. And you're done – hooray!