America went mad for breakfast cereals in the late 1800s, when the Kellogg brothers founded the Battle Creek Sanitarium and the Sanitas Food Company, advocating a diet rich in whole grains. Rival cereal maker C. W. Post, a former patient at Battle Creek, created Grape-Nuts in 1897. The pudding came soon after. We found a recipe for Grape-Nut pudding in a 1901 church cookbook published by the Dudley Street Baptist Church in Boston, but the dish appears to have gained wider national popularity by the 1920s. It seems that New Englanders have a particular fondness for this creamy custard with its cereal “crust” on the bottom, and many of our region's great diners still feature it on their menus.
Heat oven to 350° and butter a 2-quart baking dish. Put milk and Grape-Nuts in a medium saucepan over medium-high heat and bring to a simmer. Remove from heat, stir, and let cool 15 minutes. In a medium-size bowl, beat eggs with sugar, vanilla, and salt. Add the cooled milk and Grape-Nuts to egg mixture and stir well. Pour into the prepared baking dish. Sprinkle nutmeg over the top. Set the baking dish into a deep roasting pan.
Place in the oven and pour water into the roasting pan, enough to reach halfway up the side of the dish. Bake until almost set in the center, 50 to 60 minutes. There should be a very slight jiggle when you shake the pan and a knife inserted into the center should come out clean. Let the pudding set atop the stove for at least 20 minutes before serving. Serve plain or with whipped cream.