Cup measures are NZ metric cups (250 ml). US cups are 240 ml, so weigh where you can — the coconut and flour especially. With only ½ cup of flour in the whole batch, a light scoop is a big percentage swing.
Coconut is the whole recipe. Finely desiccated coconut is the sponge — it soaks up the butter and golden syrup and binds the dough. Get this wrong and the biscuits melt into toffee lace instead of holding a shape.
US substitution. American supermarkets default to sweetened flake coconut, which is the wrong thing twice over: the shreds are too long to absorb properly, and it carries added sugar plus humectants that keep it moist. Buy unsweetened desiccated instead — Bob's Red Mill, Let's Do Organic, or any Indian or Asian grocer.
If you only have flake: pulse it in a food processor or spice grinder in one-second bursts until it's crumb-fine. Don't run it continuously or it turns to coconut butter. Then weigh 55 g — grinding collapses the volume, so the cup measure no longer applies.
A grater or shredder won't work. You need it chopped shorter, not shredded longer.
Cold trays. Warm trays start the butter running before the biscuits hit the oven. Between batches, use a second tray or run the first one under cold water and dry it.
Convection ovens. Samsung and most US ovens run Auto Conversion by default, which silently subtracts 25°F when you're in a convection mode. Since 180°C here is a conventional temperature, either switch that setting off or just use regular Bake at 350°F.
Doneness. Golden, not amber. Deep caramel colour means they've gone past biscuit and into toffee.
