Preheat your oven to 180 degrees celsius and line an 18 x 28cm slice tin with baking paper.
Place the butter, golden syrup and brown sugar into the Thermomix bowl and cook for 2 minutes, 100 degrees, speed 2 to melt.
Scrape down the sides of the bowl and add the bicarbonate of soda and mix for 10 seconds on Speed 3.
Add the rolled oats, plain flour and coconut and mix for 20 seconds, REVERSE, Speed 2 to combine. Scrape down the sides of the bowl and mix for a further 10 seconds, REVER, speed 2 until combined.
Place the mixture into the tray and press down firmly before popping it into the oven to bake for 25 minutes or until lightly golden brown.
Leave the Anzac Slice in the baking tray to cool for 10 minutes before transferring to a wire rack to cool completely.