If the food or dish is affiliated with a holiday or has religious significance, look for books and articles about the food and the holiday or religion. For example:
Search for books or articles about the history of a key ingredient in the dish or about the dish itself. Reaktion publishes an Edible series on single food items. There are also many other books on single foods or dishes:
If you are researching a particular regional food or dish, look at the Gastronomy research guides and course guides with the title "Culture and Cuisine of..." to see if there are encyclopedias, cookbooks, or other books on your country or region, or on an immigrant population who brought their foodways to another country.