From their vantage point, Annabelle’s parents admired the room, cooing over the photographs that seemed to cover every available surface and marvelling at the size of the textbooks that lay open on Annabelle’s desk.
“Looks lovely, darling,” her mother said. “Very homey.” She handed Annabelle a chocolate sandwich cake filled with buttercream. “Here, I made you this. Your favourite.” Annabelle swooned and took the plate from her. “Mary sends her love,” her mother added.
“I see you’ve broken the habit of a lifetime and made your bed,” her father said. Annabelle snorted.

Put 85g/3 oz of the sugar in to a pan with the cocoa powder and water. Bring to a boil and simmer gently for a few minutes until smooth, stirring constantly. Leave to cool.

Sift the flour and remaining dry ingredients into a mixing bowl. Cream together the remaining sugar and the butter until fluffy, then beat in the vanilla essence and the egg yolks until the mixture is light. Stir in the cooled cocoa mixture and fold in the dry ingredients alternately with the soured cream. Beat the egg whites until stiff, then fold into the cake mixture until evenly mixed.

Pour the mixture into a deep 18cm/7-inch round greased cake tin. Bake in a moderate oven 175°C/350°F/Gas Mark 4 for about 1¼ hours or until a skewer inserted in the centre comes out clean. Remove the cake from the oven and leave to cool for about five minutes. Transfer to a wire rack to cool completely.

To prepare the icing, beat the butter with an electric beater or wooden spoon until light and fluffy. Gradually beat in the icing sugar until thoroughly mixed. Put the chocolate pieces in a heatproof bowl with the milk and stand over a pan of hot water until melted, stirring occasionally. Stir into the butter and icing sugar mixture.

Cut the cake into two layers. Spread the bottom layer with three-quarters of the frosting and re-shape the cake. Spread the top with the remaining frosting and sprinkle around the edge with chopped nuts.