Here’s a fruitcake variation that people actually love: tender frosted bars studded with dried fruit, nuts, and chocolate (that’s the “treasure”). Treasure-chest bars were popular in the ’60s and ’70s, and we published this version of the recipe in November 1978.
It came from Armand Riendeau, a soft-spoken French Canadian chef who operated the Pot Luck Restaurant in Berlin, New Hampshire, from 1964 until 1981. (After closing the restaurant, he opened an art studio, which he ran until his death in 1987.)
His son, Roland, remains in the restaurant business as an executive chef, and he remembers the bars well. “They had a browned-butter frosting, and that’s really different,” he says. “My dad had professional bakers who worked for him over the years, and I think one of them brought the recipe. I still have one of their cookbooks, a little brown spiral binder that has all the handwritten recipes.”
Preheat your oven to 350° and position a rack in the middle. Line a 9x13-inch baking pan with aluminum foil, draping the sheets over the sides (to make the bars easier to remove). Grease the foil with butter.
In the bowl of a standing mixer (or in a large bowl, if you’re using a handheld mixer), cream the butter, brown sugar, and granulated sugar until fluffy, about 2 minutes. Add the eggs and vanilla and beat 1 minute.
In a medium-size bowl, whisk together the flour, baking powder, and salt. Add the dry mixture to the butter mixture in three batches, alternating with the milk. Add the chocolate, nuts, and fruit, and stir to combine.
Spread the batter in the prepared pan and bake, rotating the pan halfway through, until the top is golden brown and the cake is beginning to pull away from the sides, about 30 minutes.
Meanwhile, make the frosting: In a medium-size skillet over medium heat, melt ½ stick (4 tablespoons) of butter and let it cook, stirring, until it begins to brown. Pour into the clean bowl of your mixer, and add the confectioners’ sugar, milk, vanilla, and salt. Beat the mixture until smooth.
Let the bars cool in the pan for 10 minutes; then lift by the foil to remove. Frost while still slightly warm; then cut and serve.