Preheat the oven to 160˚C. Grease and line a cake tin with parchment paper.
Place 125g of chocolate in a glass bowl set over a saucepan of simmering water on low heat. Once melted, remove the bowl from the saucepan and add the butter cube by cube, stirring until smooth. Set aside to cool slightly.
Fold in 60g of caster sugar, and ground almonds, and stir in the egg yolks into the cooled chocolate mixture. Set aside.
In a separate bowl, whisk the egg whites to a soft peak and slowly add the remaining caster sugar, beating until a light meringue texture forms. Immediately and gently fold the egg white meringue into the chocolate mixture.
Pour the batter into the prepared cake base, smooth over the top, and place it in the oven.
Bake for 35-40 minutes or until the top appears dry and a skewer inserted in the middle comes out with a few moist crumbs attached, ensuring not to overcook for a moist consistency.
Remove from the oven and let it cool completely for 2-3 hours or overnight for the best-tasting result.
Once ready, prepare the chocolate sauce. In a saucepan, bring the cream to a boil. Remove from heat and add the chopped dark chocolate. Stir until smooth, and add to a small bowl.
Dust with cocoa powder or icing sugar and serve with raspberries and chocolate sauce for an indulgent touch.