Preheat the oven to 160°C. Line 2 baking trays with silicone baking mats or baking paper.
Combine rolled oats, flour and coconut in a large bowl.
Place dextrose in a small non-stick saucepan. Heat over medium heat until melted, stirring frequently (it will take about 10 minutes to melt).
Once melted turn heat up to medium-high and heat for a further 2 minutes whilst stirring. Remove from heat.
Add butter, RMS and molasses (if using) to melted dextrose mix. Be careful as the butter might splatter a bit as it hits the hot dextrose. Stir until butter has melted.
Combine baking soda and boiling water in a small bowl and add to dextrose/butter mixture (it will foam up which is ok).
Pour liquid mixture into dry ingredients and combine thoroughly.
Drop tablespoonful lots of mixture into the prepared trays. They don’t spread too much while they are cooking so you can put them quite close together. Press the mixture down to suit how you like your biscuits...the more you flatten them, the thinner and crunchier they will be.
Bake for 12-15 minutes or until cooked to your liking. Cool on baking trays for 5 minutes then transfer to wire racks to cool completely. These are best eaten on the day, but you can store them in an airtight container for 2-3 days, they just might soften a bit over time.
* Molasses is on David’s “Unsafe” list of sweeteners because of its high fructose content. The ½ teaspoon used here delivers 1.6 grams of fructose over the whole recipe, so when you divide that out over the 25 biscuits it is very low. I have listed it as optional, so it is up to you if you want to use it. It just enhances the flavour of the biscuits a little to give them more of the authentic brown sugar/golden syrup taste.