There are a number of stories as to where this cookie came from. It's thought to be native to Nanaimo, British Columbia (hence the name), and it gained widespread popularity in the 1950s. Whatever its origins, we loved it. We added the twist of peanut butter to make a simple, delicious, no-bake bar cookie that's super kid-friendly and freezes well.
03For the filling: Beat the butter, peanut butter and confectioners' sugar together in a medium bowl with an electric mixer until light. Spread over the cookie and freeze while you prepare the chocolate glaze.
04For the glaze: Put the chocolate and butter in a medium heatproof bowl, and set over the barely simmering water. Stir occasionally until melted and smooth. Remove from the heat and let cool slightly. (Alternatively, put the chocolate and butter in a medium microwave-safe bowl. Melt at 50 percent power in the microwave until soft, about 1 minute. Stir, and continue to heat until completely melted, about 1 minute more.). When cool but still runny, pour the chocolate layer over the chilled peanut butter layer and carefully smooth out with an offset spatula. Freeze 30 minutes.
05To serve, remove from the freezer and let sit at room temperature for 5 minutes. Pull out of the pan using the foil flaps and transfer to a cutting board. Cut into 1-inch squares with a sharp knife. Serve cool or at room temperature.