Originally with a dash of sugar syrup, but, thanks to a comment by Yacha Han on Difford's Guide, presented here with maple syrup as a more appropriate...
I made this with Gooderham and Worts Whiskey (originally distilled in Toronto). A nice drink. I’ve also tried it on a rock like an Old Fashioned. Lately I’ve been adding 2 drops of saline solution and 1 drop of msg solution which changes the cocktail subtly (especially with a higher proof rye like Sazerac 100).