Why This Works
The Rob Roy is a study in the modifier's role. The vermouth isn't a background player at a 2:¾ ratio — it's contributing herbal complexity, gentle sweetness, and the wine-like roundness that turns straight spirit into a cocktail. Use a fresh, quality AF vermouth; a tired one flattens the whole drink.
Stirring, never shaking, is the rule for this family. You want density and silk, not froth — and the 30-plus seconds of stirring isn't just chilling the drink, it's adding the dilution that softens everything into one seamless line.
The Alcohol-Free Swap
A quality alcohol-free whiskey carries this drink's backbone; look for one with genuine oak character, since there's nothing here to cover for it.