Some may want to use a Demerara sugar syrup but pure cane sugar delicately mellows the malt whisky without masking its flavour, indeed it amplifies its...
This might even beat a traditional Old Fashioned for my taste. I do think the recipe is just a tiny smidge too sweet even with my 1.5:1 syrup so I have started just doing a bar spoon of syrup.
Maybe a bit of a diversion, but I made this with Glenfarclas 12, bitters and agave syrup.
Superb. Interesting which aspects of the spirit come to the fore.