Method
Grease and line a loaf tin (25cm x 12cm). Preheat oven to 170 ºC.
Put chocolate in a double-boiler bowl. Place over simmering hot water to melt the chocolate. Leave aside to cool slightly.
Beat butter, sugar and essence until light and creamy. Beat in egg yolks one at a time.
Stir in milk and add in melted chocolate gradually. Beat well to combine. Fold in sifted flour and stir in ground almonds.
Whisk egg whites until stiff. Carefully fold into the butter mixture in batches and mix well to blend.
Turn mixture out onto the prepared tin. Level out evenly and bake for 60 to 75 minutes or until cake is cooked through when tested with a skewer.
Leave cake to cool slightly in the tin before turning out onto a wire rack to cool completely.