Hazelnut Chocolate Cake

125 gm butter, chopped
125 gm dark chocolate, chopped
150 gm castor sugar
110 gm packed ground hazelnuts
150 gm self-raising flour
4 eggs
Grease deep 20cm round cake pan, cover base with baking paper.
Place butter, chocolate and sugar in medium saucepan, stir over low heat, without boiling, until butter and chocolate are malted; cool 10 minutes. Stir in nuts, flour and eggs. Pour mixture into prepared pan. Bake in moderately slow oven (160ºC)1 hour. Stand 5 minutes before turning onto wire rack to cool.