Letting some cooking television go past me a few days ago, I wondered about the “foodie talk” expression signature dish, for a recipe associated with a particular chef or restaurant (or even city, region, or country) — an upscale variant of chef’s/house/local specialty.
Sheila Clark visits with Martin Kouprie, chef at Pangaea Restaurant in Yorkville, Toronto to sample his signature dish, Mahogany Glazed Pacific Salmon. (link)
At some point in every reality TV cooking competition the contestants are asked to make their signature dish. The dish should define their culinary point of view, highlight their skills as a chef, and be incredibly delicious. (link)
Signature dish Braciolone alla Napoletana (pork roulade with prosciutto, Parmesan, and parsley) created by Chef Arturo Iengo of Ristorante Pascalucci in Benevento, Italy, for Garden Café: Italia, at the National Gallery of Art, Washington, October 14, 2008, through January 25, 2009. (link)
(There are also uses picking out historical associations between chefs or restaurants and particular dishes: for Sachertorte, Tarte Tatin, Waldorf Salad, for instance.)
A Google Books search pulls up tons of recent references to signature dishes, but they become sparser as you search back from 2000. The earliest use I found in an hour or so of searching is from 1982 (in an issue of House & Garden). Antedating is not really my thing, though, so I’ll leave this task to those who are keen about early cites.
The sense development is pretty straightforward: it’s a specialization of the ‘distinctive characteristic’ sense of the noun signature. But the specialization in the food context hasn’t made it to the OED or to AHD4. However, NOAD2 has snagged it, more or less:
a distinctive pattern, product, or characteristic by which something can be identified: the chef produced the pâté that was his signature | [as adj.] his signature dish
The specialization seems to be fairly recent, but rapidly spreading, perhaps because it has a “toney” connotation lacking in specialty. The vector for its spread seems to have been food journalism and similar sources (like restaurant reviews, travel literature, food and cooking shows on television).