Start by pre-heating your oven to 150C/300F. Grease a 9" springform cake tin with butter and place a circle of parchment paper at the bottom. Tip a tbsp of cocoa powder in and shake it around so the edges of the tin are coated in cocoa powder.

In a medium bowl, add the chocolate & butter and melt it gently over a bain-marie and then set it to one side to cool.

In a separate bowl, whisk together the salt, sugar, eggs, egg yolks & vanilla paste until smooth. Then tip in the cocoa powder and ground almonds and whisk to combine. Once mixed, pour in the melted chocolate mixture and whisk together until everything is evenly combined.

In the bowl of a stand mixer, or in a separate large bowl and using a hand mixer, whisk the egg whites until they are frothy then slowly tip in the sugar just a little at a time. Whisk until the egg whites hold a stiff-ish peak.

Fold the egg whites in thirds, relatively gently into the chocolate mixture making sure to scrape the bottom of the bowl to incorporate all of the chocolate mixture into the egg whites. Once it is all mixed in and there is no visible egg white left, pour the mixture into your lined cake tin. Bake in the oven for 25 minutes then remove and allow to cool to room temperature.

Once the cake is cooled, I liked to refrigerate it for 2-3 hours as I think it helps to make the cake even denser which I love! You can also leave it in the fridge overnight and serve it the next day.

To decorate, flip the cake over so the smooth side is at the top and place individual strips of baking parchment on top of the cake, leaving about 1/2" gap in between each one. Dust a coating of icing sugar all over the cake then carefully peel off the parchment paper. Then, cover the strips of icing sugar you just dusted with more parchment paper and dust the gaps with cocoa powder (this stops the cocoa powder from getting all over your icing sugar strips!). It can be a little messy and difficult so this step is totally not necessary!