Preheat oven to 180°C (355°F). Grease a 20cm round spring-form cake tin. Line the base and sides with baking powder.
In a heatproof jug, place the coffee and boiling water and stir gently until it dissolves.
In a saucepan set over a low heat, place spread, chocolate, cocoa powder and coffee mixture and heat, stirring constantly, for 2 minutes, until spread and chocolate are melted. Remove from heat and set aside to cool slightly.
In a bowl, place egg yolks and brown sugar and beat using an electric mixer for 5 minutes, or until thick. In a separate bowl, using an electric mixer, beat egg whites until soft peaks form.
Combine chocolate mixture with egg yolk mixture and the hazelnut meal and fold together. using a large metal spoon, fold half the egg whites into the mixture until just combined. Fold in the remaining egg whites.
Into the prepared pan, pour batter and smooth surface. bake for 45-50 minutes, or until a skewer comes out clean. Cool cake completely in pan. Dust with extra cocoa powder.
Slice the cake and serve with yoghurt and mixed berries.