A thin veil of fear and mystery, like the snowy fog that half hides slick black tree trunks at the dark end of December, clings to the very mention of Christmas pudding. It rattles like a strange and bony relic of a past half forgotten, one of hams pierced a thousand times with the blunt brown tips of whole cloves, sideboards sagging with tawny port, Armagnac and Amontillado in bottles that glisten like crown jewels or the pride of a dragon’s hoard, and, in the kitchen, a sleeping beast at the bottom of a stockpot snoring on the stovetop since the first glint of Christmas dawn—the pudding itself, belching out clouds of steam so thick you could cut them with a trowel, and dreaming,…