Preparation

• bottom layer:
  Melt butter, sugar, and cocoa in a heavy saucepan.
  Add beaten egg and stir to cook and thicken. Remove from heat . Stir in crumbs, coconut and walnuts.
  Press firmly into ungreased 9 by 9 inch pan.
  Second layer:
  Cream butter, milk, custard powder and icing sugar together well. Beat until light. Spread over bottom layer.
  Third layer:
  Melt chips and butter over low heat. Cool. When cool but still runny, spread over second layer. Chill in refrigerator. Cut into 36 squares.