The history of the Anzac biscuit can be traced back to the 1700s - and contrary to popular belief, it did not evolve from the Scottish oat cake, a culinary historian says.
Australian-based historian Allison Reynolds told RNZ's Anzac Morning that the precursor to the Anzac biscuit was featured in a 1747 book by Englishwoman Hannah Glasse, called The Art of Cookery Made Plain and Easy.
The biscuit was not identical to today's Anzac biscuit but featured many of the same ingredients and the same method of making, using melted butter, she said.
Many people believed it evolved from the oat cake, but that was not true, she said. Anzac biscuits used rolled oats, while oat cakes used ground oat meal.
Oat cakes and Anzac biscuits were also made, baked and served differently.
Reynolds said the biscuits Kiwis knew and loved today were perfected by Scottish migrants to both Australia and New Zealand.
"The biscuits I like to say were created simultaneously in both countries."
Prior to 1915, they were known by other names, such as 'nutties' or 'munchies', she said.
During World War I, wives and mothers began sending the biscuits to soldiers at the front, and they became known as 'Red Cross biscuits' or 'soldiers' biscuits'.
"They wanted to send something nutritious because they were worried the troops weren't getting that well fed."
Earlier versions featured two biscuits sandwiched together with jam, but that changed during the war years.
Eggs were also removed from the recipe at that time and golden syrup was added, Reynolds said.
"The sensible wives and mothers knew that the biscuits would not keep long and because of the war rationing, eggs were not always in ready supply."
As well as being sent to soldiers and nurses at the front, the biscuits were baked for fundraisers for the war effort.
They became known as Anzac biscuits sometime after the formation of the Australian and New Zealand Army Corps in 1914.
Reynolds said the first printed reference to that name that she could find was in the eighth edition of the St Andrew's Cookbook, which was published in 1919.
However, there was often a lag of two or three years between when a recipe became popular and when it was published in a cookbook, she said.
Reynolds said golden syrup was "absolutely essential" to Anzac biscuits - "don't change it for honey, don't change it for anything else".
It should come from a tin rather than a squeezy bottle, as bottled golden syrup was often more liquid, she said.
Check out Reynolds' recipes for both chewy and crispy Anzac biscuits here.