Sydney Smith (1771-1845) in 1839 letter to his daughter, Lady Holland. [from: A memoir of the Reverend Sydney Smith. by his daughter, Lady Holland. With a selection from his letters ... 1855].
and from: Eliza Leslie. The Lady's Receipt-book. Phila: 1847
SYDNEY SMITH'S SALAD-DRESSING.
Have ready two well-boiled potatoes, peeled and rubbed through a sieve; they will give peculiar smoothness to the mixture. Also, a very small portion of raw onion, not more than a quarter of a tea-spoonful, (as the presence of the onion is to be scarcely hinted,) and the pounded yolks of two hard-boiled eggs. Mix these ingredients on a deep plate with two small tea-spoonfuls of salt; one of made mustard ; three table-spoonfuls of olive oil; and one table- spoonful of vinegar. Add, lastly, a tea-spoonful of essence of anchovy; mash, and mix the whole together (using a boxwood spoon) and see that all the articles are thoroughly amalgamated. Having cut up a sufficiency of lettuce, (that has been well washed in cold water, and drained,) add to it the dressing immediately before dinner, mixing the lettuce through it with a boxwood fork.
This salad dressing was invented by the Rev. Sydney Smith, whose genius as a writer and a wit is well-known on both sides the Atlantic. If exactly followed, it will be found very fine on trial; no peculiar flavour predominating, but excellent as a whole. The above directions are taken from a manuscript receipt given by Mr. Smith to an American gentleman then in London.
In preparing this, or any other salad-dressing, take care not to use that excessively pungent and deleterious combination of drugs which is now so frequently imposed upon the public, as the best white wine vinegar. In reality, it has no vinous material about it, and it may be known by its violent and disagreeable sharpness, which overpowers and destroys the taste (and also the substance) of whatever it is mixed with. And it is also very unwholesome. Its colour is always very pale, and it is nearly as clear as water. No one should buy or use it. The first quality of real cider vinegar is good for all purposes.
The above receipt may be tried for lobster-dressing.
History & source of name
How stuff works
To Dress Salad, Mary Randolph. The Virginia Housewife. Baltimore: 1838