Mix together all of the ingredients in a medium saucepan.
Place the saucepan over high heat.
Stir until the butter and the sugar has dissolved.
Bring the mixture to the boil and cook for about 5 minutes, stirring regularly until it is smooth and has thickened in texture.
Pour the sauce into a small jug.
The sauce will thicken as it cools.
Kitchen Notes
Keep any leftover sauce in the fridge in a glass jar.
To reheat, simply spoon the cold sauce into a small saucepan and heat gently until it is warm.
Golden syrup has a distinct taste which, I think, is hard to substitute. However, a common substitute in the US is light corn syrup.
OVEN & STOVE TEMPERATURES All recipes on this website have been tested on an induction stove and/or with a conventional oven (i.e. an oven without fan). All recipes on this website use temperatures for a conventional oven, unless otherwise mentioned. Convection ovens (i.e. fan-forced ovens) are typically 20°C/70°F hotter than conventional ovens, but please check your manufacturer’s handbook.