To construct the pudding's complex flavors, Wayman begins by roasting Beauregard sweet potatoes until slivers of the caramelized flesh burst through cracks in the skins. He cooks white onions slowly over low heat to coax out their sweetness, in a mixture of bacon fat and butter seasoned with garlic, sage, wild bay, and cayenne. Once the onions are translucent, he adds cream and the roasted potatoes, bringing the mixture to a simmer and then gently cooking it for several minutes more. He places it into a blender, adding the egg yolks one by one to prevent curdling. Finally, he bakes the pudding in a bain-marie, a pan set into a larger pan filled with hot water; doing so prevents a crust from forming on the outside of the custard before it is fully cooked and firm. He serves the pudding warm from the oven, with mushrooms sautéed in garlic and butter.