Preheat the oven to 350°F (180°C), or 160°C for a fan oven. Line a baking sheet with parchment paper or silicone baking mat and set aside.
In a mixing bowl, combine flour with oats, coconut, and sugars. Set aside.
In a small saucepan, combine butter with golden syrup and melt the butter, keep stirring until completely melted. Add the baking soda and stir it in, the mixture will foam, immediately remove from heat.
Pour the mixture over the dry ingredient mixture, and mix with a spatula until combined. You want the mixture to hold its shape, add water 1 tablespoon at a time until it’s no longer dry.
Use a 1 tablespoon size cookie scoop, scoop out cookie dough and shape into balls. Lightly flatten with your hands and place on the prepared cookie sheets about an inch apart.
Bake in the preheated oven for 12 minutes for chewy cookies, or 15 minutes for crispy cookies. Allow to cool on the cookie sheets for 10 minutes, then serve.
Notes
Water Amount: Different brands of oats will have different liquid absorbency, so you'll need to add just enough water to be able to shape the cookie dough into balls. If you add too much and the mixture becomes sticky, add a little bit of flour and mix again.
Don't overcook the syrup: You only need to heat the syrup and butter until the mixture is melted and smooth. Then stir in the baking soda and immediately remove the mixture from the heat. If the caramel cooks too long, you will end up with very hard cookies.
For chewier biscuits, bake the cookies for a few minutes less. Note that the cookies will be soft straight from the oven and will harden as they cool.
Use a cookie scoop to make evenly-sized biscuits. You should be able to make 30 cookies with a 1-tablespoon scoop or 20 larger cookies with a 1.5-tablespoon cookie scoop.
To Store: Keep the cookies in an airtight container at room temperature for up to a week.