Heat oven to 180C/160C fan/gas 4. Grease a 33 x 23cm Swiss roll tin and line with baking parchment, then grease the parchment too. Tip the chocolate into a heatproof bowl and place it over a pan of gently simmering water. Leave to melt, stirring occasionally, then remove from the heat and allow to cool a little (alternatively, melt it in short bursts in the microwave).
Put the egg whites in a large, clean bowl, and the yolks and sugar in another. With very clean beaters, whisk the whites until they are just holding soft peaks. Transfer the beaters to the yolks bowl (no need to wash them) and beat until the sugar has dissolved and the mixture is thick and pale.
Add a large spoonful of whites to the yolks and mix with a large metal spoon to loosen the yolks a little. Add the remaining whites and gently fold into the yolks, avoiding knocking out too much air.
When nearly all incorporated, sieve the cocoa over the surface, scatter over the almonds and pour in the melted chocolate. Continue folding until the mixture is well combined, then scrape into your tin. Spread the mixture to the edges and level the surface. Bake for 15-18 mins on the middle shelf of the oven until the surface is crisp and the cake feels springy.
While still warm, turn the roulade out onto a large piece of baking parchment, removing the parchment you used to bake the roulade on. With a small serrated knife, make a shallow incision about 1cm in from one of the shorter edges, making sure that you don’t cut all the way thorough. Starting from this end, roll up as tightly as you can, bending the cut piece inwards to get the centre of the roll tight, using the baking parchment to help you and stop the layers sticking. Leave to set and cool.
Tip the mascarpone, cream, Malibu (if using) and icing sugar into a bowl and whisk until softly whipped. Carefully unroll the roulade – it will crack in places, but don’t worry. Spread a third of the cream all over the surface, leaving a border of about 1.5cm all the way around. Drizzle the passion fruit curd all over the surface and top evenly with the passion fruit flesh.
Starting from the end that you used before, re-roll the roulade as tightly as you can, bending the cut piece into the cream to get the centre of the roll tight. Place the roulade, seam-side down, on a serving plate or board and spread the remaining cream all over the outside. Press the coconut flakes all over the top and sides, and dust with a little gold glitter, if you like. Chill and serve within a few hours. Leftovers will keep in the fridge for 2 days.