The army biscuit, also known as an Anzac wafer or Anzac tile, is essentially a long shelf-life, hard tack biscuit, eaten as a substitute for bread. Unlike bread, though, the biscuits are very, very hard. Some soldiers preferred to grind them up and eat as porridge.
The popular Anzac biscuit is a traditional, eggless sweet biscuit. Ingredients include rolled oats, sugar, plain flour, coconut, butter, golden syrup or treacle, bi-carbonate of soda and boiling water.