225g dark chocolate
1 Tbsp water
4 eggs, separated
1/4 cup Chelsea Icing Sugar
3/4 cup Chelsea Caster Sugar

Chantilly Cream
300 ml cream
1 tbsp Chelsea Icing Sugar (or Chelsea Flavoured Icing Sugar)
1 tsp vanilla essence

Preheat oven to 180°C. Line a Swiss roll tin, approximately 20x30cm with baking paper.
Gently melt the chocolate with the water (this can be done in a microwave). Whisk the egg yolks with the Chelsea Icing Sugar until thickened, then whisk into the melted chocolate.
In a separate bowl, with clean beaters, whisk the egg whites until stiff. Slowly beat in the Chelsea Caster Sugar until the mixture is stiff, white and glossy. Lightly fold the egg white mixture into the chocolate mixture.
Spread into the prepared tin and bake for 25–30 minutes until firm. Cool in the tin for 5 minutes then cover with a clean damp tea towel. Cool completely and refrigerate for 6-8 hours or overnight.
Just before serving, using the baking paper, lift out of the tin. Spread with Chantilly cream and roll up like a Swiss roll. If desired, serve with a chocolate sauce drizzled over.

Chantilly Cream:
Whip the cream with the Chelsea Icing Sugar and vanilla essence until soft peaks form in the cream.