Preheat your oven to 180°C (356°F). Line a round cake tin with parchment paper.

Beat the egg whites until soft peaks form. Gradually add 120 g of sugar, continuing to beat until stiff peaks are achieved.

Fold in the ground biscuits and walnuts gently until just combined.

Pour the mixture into the prepared cake tin, smoothing the top with a spatula.

Bake for about 25-30 minutes, or until a toothpick inserted into the center comes out clean. Let it cool completely.

Whisk together the egg yolks and 130 g of sugar until pale and creamy.

Mix the flour into the egg yolk mixture gradually, then slowly add the milk, ensuring there are no lumps.

Cook this mixture over low heat, stirring continuously until it thickens. Once thickened, remove from heat.

Melt the chocolate with raspberries and mix it into the custard. Let it cool slightly.

Beat the margarine or butter until light and fluffy, then gradually mix it into the cooled chocolate custard until well combined.

Place the cake base on a serving plate. If the cake has domed, you may wish to level it with a knife.

Spread a thin layer of the chocolate raspberry cream over the base.

Sprinkle a layer of crushed plasma biscuits over the cream.

Cover with the remaining cream, smoothing the top.

Whip the whipping cream until stiff peaks form, then spread over the top of the cake.

Melt the cooking chocolate and drizzle over the whipped cream for a decorative finish.

Sprinkle ground walnuts around the edges or over the top for added texture and flavor.

Refrigerate the cake for at least 4 hours, or overnight, to allow the flavors to meld and the cream to set.

Serve chilled, cutting into slices to reveal the beautiful layers.