I hope this answers your questions:
During World War 1, the wives, mothers and girlfriends of the Australian soldiers were concerned for the nutritional value of the food being supplied to their men. Here was a problem. Any food they sent to the fighting men had to be carried in the ships of the Merchant Navy. Most of these were lucky to maintain a speed of ten knots (18.5 kilometers per hour). Most had no refrigerated facilities, so any food sent had to be able to remain edible after periods in excess of two months. A body of women came up with the answer - a biscuit with all the nutritional value possible. The basis was a Scottish recipe using rolled oats. These oats were used extensively in Scotland, especially for a heavy porridge that helped counteract the extremely cold climate.
The ingredients they used were: rolled oats, sugar, plain flour, coconut, butter, golden syrup or treacle, bi-carbonate of soda and boiling water. All these items did not readily spoil. At first the biscuits were called Soldiers’ Biscuits, but after the landing on Gallipoli, they were renamed ANZAC Biscuits.
A point of interest is the lack of eggs to bind the ANZAC biscuit mixture together. Because of the war, many of the poultry farmers had joined the services, thus, eggs were scarce. The binding agent for the biscuits was golden syrup or treacle. Eggs that were sent long distances were coated with a product called ke peg (like Vaseline) then packed in air tight containers filled with sand to cushion the eggs and keep out the air.
As the war drew on, many groups like the CWA (Country Women’s Association), church groups, schools and other women’s organisations devoted a great deal of time to the making of ANZAC biscuits. To ensure that the biscuits remained crisp, they were packed in used tins, such as Billy Tea tins. You can see some of these tins appearing in your supermarket as exact replicas of the ones of earlier years. Look around. The tins were airtight, thus no moisture in the air was able to soak into the biscuits and make them soft. Most people would agree there is nothing worse than a soft biscuit.
During World War 2, with refrigeration in so many Merchant Navy Ships, the biscuits were not made to any great extent. It was now possible to send a greater variety of food, like fruit cake.
ANZAC biscuits are still made today. They can also be purchased from supermarkets and specialty biscuit shops. Around ANZAC Day, these biscuits are also often used by veterans’ organisations to raise funds for the care and welfare of aged war veterans.
This is from an Australian ANZAC Day site.
The biscuits have become an Australian classic, along with pavlova, lamingtons, meat pies etc.
Glad they are doing so well for you all the way over in Holland.
PS: They are traditionally made as biscuits (cookies)