The Rob Roy is an old cocktail. It was invented at the Waldorf Hotel in the 1890s in New York. Named for a Broadway show with the same name, the Rob Roy is similar to a Manhattan with the bourbon substituted for blended scotch.
1 1/2 oz Scotch
1/4 oz sweet vermouth
Angostura bitters to taste
Maraschino cherry for garnish
Shake scotch, vermouth, and bitters well with cracked ice, strain into a chilled cocktail glass and garnish with a cherry.