n. — Food
a dessert square with three layers: a crumb base, a layer of buttercream, and melted chocolate icing.
Type: 1. Origin — The recipe for what is called Nanaimo bars in Canada seems to have come from England (see the 1988 quotation). However, the Vancouver Sun's Edith Adams (an invented persona who presided over the newspaper's cookery columns and contests) merely re-named the bars based on knowledge of recipes originating there (Newman 2014). She then produced a recipe with that name in the Fourteenth Prize Cookbook (1953). It travelled fast. OED-3 lists its earliest attestation as an Alberta source from 1954 (see OED-3, s.v. "Nanaimo bar") and Barber (2007: 127) dates it to a Saskatchewan cookbook from 1956. Quotations (e.g. the 1988, 1992 and 2003 quotations) demonstrate the widespread speculation about the term's origin.
Nanaimo bars have become popular internationally, but the term remains most prevalent in Canada (see Chart 1). Some sources suggest that the Nanaimo bar is on par with dishes such as poutine as a marker of Canadian identity (see, e.g. the 2007 quotation).
See also COD-2, s.v. "Nanaimo bar", which is marked "Cdn", and ITP Nelson, s.v. "Nanaimo bar", which is marked "Canadian".
See also: dainty poutine (meaning 1) butter tart
- According to Newman (2014), the 1953 Vancouver Sun article (11 April, p. 30) refers to London Fog bars as “also called Nanaimo bars”.
- 1953  London Smog Bars [...] Melt chocolate over hot water; add butter and blend well. Spread over custard icing. Let harden. (These are also called Nanaimo Bars. --E.A[X]). 
- 1954  NANAIMO BARS
½ cup butter
¼ cup granulated sugar
5 tablespoons cocoa
1 teaspoon vanilla [...] 
- 1968  NANAIMO BARS
½ cup butter
¼ cup sugar [...] 
- 1974  Nanaimo bars ½ cup butter ¾ cup granulated sugar [...] 
- 1988  NANAIMO BARS: In the early 1950s, a Vancouver Island housewife entered a magazine cooking contest. Driven by civic pride, she called her squares - chocolate-coconut crust, custard filling, chocolate on top - Nanaimo bars. 
- 1992  Sometime in the late 1940s, a modest housewife in Nanaimo, a coal-mining town 110 kilometres north of Victoria on Vancouver Island, entered a magazine cooking contest with her recipe for easy no-bake squares.
Setting aside personal glory, she called them Nanaimo bars.
The bars were winners: a layer of dark chocolate topping, a buttery cream filling, a chewy chocolate-coconut-crumb-nut-base. 
- 1998  Few desserts are more Canadian or as addictive as Nanaimo bars, according to the New Chatelaine Cookbook. 
- 1999  The Original Nanaimo Bar Recipe
What you've really been waiting for: on the following page is a transcription of what is likely the first known publication of the recipe for the now world famous Nanaimo Bar. It appears in a 118-page stapled book entitled Favorite Recipes, Compiled by the Women's Association of the Brechin United Church, which is in Nanaimo, British Columbia, Canada. The originator of the Nanaimo Bar appears to be Joy Willgress of Nanaimo. The date of this recipe book is not given, but advertising in the book suggests circa 1955.
- 2003  [...] a letter-writing campaign to create Canadian stamps honouring not only the donair, but the Nanaimo bar (invented in British Columbia in the 1930s), the butter tart (Ontario, 1920s) and even [...] 
- 2007  While Smarties, Nanaimo bars and the caloric goodness of Tim Horton's may be closely associated with the Canadian identity, Canadians still manage to be healthier eaters than our neighbours south of the border. According to Statistics Canada, we eat more fish, fruits, vegetables and drink more two per cent (as opposed to whole) milk than Americans. 
- 2010  It is was great to see your newspaper add a bit more about the mystery of the Nanaimo bar.
Its origins are unclear, but I have in front of me what might be one of the earliest printed versions of it (the earliest I know of, anyway).
It appears in Favorite Recipes, Compiled by the Women's Association of the Brechin United Church, submitted by Joy Willgress. It seems to have been printed in the early 1950s. 
- 2016  Thumbs Up: To the White House, for including B.C.'s famous dessert, Nanaimo bars, on the menu for Thursday's state dinner that marked Justin Trudeau's first prime ministerial visit to the U.S.