1 oz Scotch (pref cask strength)
1 oz Dry vermouth
1 oz Sweet vermouth
1 twst Lemon peel (expressed and discarded)
Stir, strain, straight up, cocktail glass, express lemon peel and discard
A cask-strength scotch will give good alcohol balance. Essentially a Perfect Rob Roy with an inverted ratio (more vermouth than scotch).
Savoy Cocktail Book
Scotch, Dry vermouth, Sweet vermouth, Bitters, Lemon peel