Historic Food claims the trayne roste is a direct ancestor of the gâteau à la broche, which is neat if it's true. Blanched almonds and dried nuts are threaded on a thread as long as a man is tall. That gets coiled around the spit and drizzled with a batter made of flour, wine or ale, ginger, sugar, saffron, cloves, salt, and other spices. AND THAT'S HOW YOU TRAYNE ROSTE.
A trayne roste, nearly done. [source]
Slices showing the cake anatomy. [ibid.]