Preheat oven to 160 degrees celsius (fan-forced). Grease and line three flat baking trays with baking paper.
Place the butter, golden syrup and brown sugar into the Thermomix bowl. Melt for 3 minutes, 100 degrees, Speed 2.
Add the bicarbonate of soda and the cold water to the melted butter mixture and mix for 10 seconds, Speed 3.
Add the rolled oats, plain flour and coconut. Mix together for 40 seconds, Reverse, Speed 2.
Roll tablespoons of the ANZAC dough into balls. Place on trays, 5cm apart and flatten slightly.
For chewy Thermomix ANZACS, bake for 10 to 12 minutes or until lightly golden. For crunchier ANZAC biscuits, increase the cooking time to 12-15 minutes.
Allow to cool on the baking trays for 5 minutes before transferring to a wire rack to cool completely.