My sister introduced this winner to the family repertoire and she serves it with a dark chocolate ganache and thick cream.
125 g butter, chopped into 5 cm pieces
100 g dark chocolate, roughly chopped
1 cup boiling water
1 cup castor sugar
1 teaspoon pure vanilla
2 eggs, separated
½ cup sour cream
1 teaspoon bicarbonate of soda
2 cups self-raising flour
pinch of salt
Chocolate and honey icing
200 g bittersweet chocolate, grated or chopped
80 g unsalted butter
2 tablespoons honey
Preheat oven to 180°C. Butter a 22 cm springform tin well and dust with flour. Tap out excess.
Put butter and chocolate into a large bowl and pour over boiling water. Leave to stand for 5 minutes, then stir to ensure that chocolate and butter have melted. Stir in sugar and vanilla. Beat in egg yolks one at a time, blending thoroughly. Combine sour cream and bicarbonate of soda and beat into chocolate mixture. Sift in flour and salt, combining well.
Beat egg whites to soft creamy peaks and lightly fold into chocolate mixture. Pour into prepared tin and bake for 40–50 minutes or until cake is firm to touch and beginning to shrink from sides of tin. Allow cake to cool in tin for a few minutes before turning it out onto a wire rack cool completely.
For the icing, put all ingredients into a small bowl and rest bowl over a small saucepan of hot water over gentle heat until chocolate has melted. Stir gently to combine. Pour icing over cake and tilt cake so icing runs down the sides.