Review:

Scotch whisky's answer to the Manhattan. The Rob Roy is classically made with Angostura Bitters, but in his 1948 The Fine Art of Mixing Drinks, as a footnote below his recipe, David Embury attests "Peychaud, somehow, seems to blend better than Angostura with Scotch."

I find Abbott's Bitters combines more harmoniously with the whisky in this cocktail. Or if not to hand, I use one dash Angostura-style aromatic bitters and one dash Peychaud's/creole bitters. Whatever bitters you use, their inclusion is essential to the balance and complexity of this cocktail.

Variant:

Made with orange bitters this becomes a Highland or Highlander cocktail.
White Rob Roy

History:

Named after the Rob Roy operetta about the Scottish folk hero and outlaw Robert Roy MacGregor, which debuted on Broadway on 29th October 1894. The theatre was near where New York's Waldorf Astoria Hotel used to stand (The Empire State Building occupies the site today) so it was thought the cocktail was created at the hotel to serve operagoers, and that scotch whisky was appropriately swapped for the usual American whisky in the popular cocktail of the day, a Manhattan. So, a Scotch whisky-based Manhattan become known as a Rob Roy.

The New York Times 30th October 1894 review said "the latest work of Harry B. Smith and Reginald De Koven" was "clean, frank, manly, bright, and winesome." The same words could have been used to describe the cocktail, and before cocktail historian David Wondrich uncovered more about this cocktail, the above served as a neat, concise origin story.

It turns out there was a cocktail named "Rob Roy" created some 20 years earlier by New York bartender Edward F. Barry, and this is documented in an interview he gave for the New York Sun 22nd August 1873.
"The Rob Roy cocktail is made with a little gum syrup, two dashes of Angostura, a few drops of oychette cordial [orgeat], in a tumbler filled with fine ice, strained."
Sadly, the newspaper doesn't record what the base spirit to this cocktail was. If it was Scotch whisky then this could be the forerunner to the modern-day Rob Roy, but chances are, it's an unconnected recipe that did not stand the test of time.

It's worth noting that the first known recipe for a scotch whisky-based "Manhattan" [what we now call a Rob Roy], which appears in Charlie Paul's American and other Drinks, published 1884 in London, has no reference to the cocktail also being known as a Rob Roy.

MANHATTAN COCKTAIL.
Fill tumbler with chipped ice; put in three or four drops of angostura bitters, ditto of plain syrup; and half a liqueur glassful of vermouth, half wine glassful of scotch whiskey; stir well with spoon and put a small piece of lemon on top.

Charlie Paul, 1884

The earliest "Rob Roy" named recipe based on scotch whiskey appears in James C. Maloney's 1900 The 20th Century Guide For Mixing Fancy Drinks (published in Chicago, Illinois), but with lemon juice and other estranged ingredients to a modern-day Rob Roy.

ROB ROY COCKTAIL.
Fill mixing glass two-thirds full fine ice.
¼ teaspoon of lemon juice.
1 teaspoon of syrup.
2 dashes of orange bitters.
1 dash Peychaud's bitters.
12-3 wine glass Scotch whisky.
1-3 wine glass French Vermouth.
Stir well and strain into cocktail glass and serve.

James C. Maloney, The 20th Century Guide For Mixing Fancy Drinks, 1900

Just a year later, another "Rob Roy" recipe surfaces in the anonymously written 1901 The Cocktail Book a Sideboard Manual for Gentlemen (published in Boston, Massachusetts), and this recipe is the first to be recognisable as scotch whisky-based Manhattan, albeit with orange bitters (rather than aromatic bitters).

Rob Roy Cocktail.
Use Mixing Glass.
Two dashes orange bitters; two-thirds Scotch whiskey; one-third Italian vermouth. Fill with ice, mix, and strain into a cocktail glass. Serve an olive in the glass.

The Cocktail Book a Sideboard Manual for Gentlemen, 1901

Tellingly, another Rob Roy recipe, with the same proportions and ingredients, appears in the "New And Up-To-Date Drinks" appendix at the back of Thomas Stuart's 1904 book Stuart's Fancy Drinks And How To Mix Them}.

Rob Roy Cocktail.
1 dash orange bitters.
⅔ Scotch whiskey.
⅓ Italian vermouth.

Thomas Stuart, Stuart's Fancy Drinks And How To Mix Them, 1904

Then, the 1909 edition of The Cocktail Book a Sideboard Manual for Gentlemen (published in London, England) gives an updated recipe. this time calling for Angostura Aromatic Bitters. The only thing in this 1909 recipe that differs from modern renditions its being garnished with an olive, rather than the modern preference for a cherry.

Rob Roy Cocktail.
Use Mixing Glass.
THREE dashes Angostura bitters; two-thirds Scotch whiskey; one-third Italian vermouth. Fill with ice, mix, and strain into a cocktail glass. Serve an olive in the glass.

The Cocktail Book a Sideboard Manual for Gentlemen, 1909

So, by 1909, the modern-day Rob Roy being a Scotch whisky-based Manhattan was established. Well, that would be the case if it wasn't for the erroneous apple brandy, vermouth and gomme syrup "Rob Roy Cocktail" in Paul E. Lowe's 1909 Drinks : How To Mix And How To Serve (published in London, England). I'm guessing this is simply a variation, what we now call a "riff" and is best ignored.

Rob Roy Cocktail
2 dashes gum syrup.
½ jigger apple brandy.
½ jigger Vermouth.
Stir; strain into cocktail glass and serve.

Paul E. Lowe, 1909

As to who first made a Scotch whisky-based Manhattan that went by the name "Rob Roy, perhaps David Wondrich found the answer in a 24th March 1941 edition of the New York Sun, and a letter to G. Selmer Fougner's Along The Wine Trail column. The writer is the brother of Henry August Orphal, a bartender at the Duke's House in New Jersey. The letter describes how his brother was put on the spot by a representative of Usher's to create a cocktail using his blended scotch whisky. Appreciative of the new cocktail, the salesman named it the Rob Roy.

Nutrition:

One serving of Rob Roy contains 179 calories