Useful pages by me
Useful pages by others
Kurtos.EU – a comprehensive site listing businesses, recipes, and histories. Mostly focused on chimney cakes, but still has plenty of information on tree cakes.
Historical works and journal articles
"The Baumkuchen Family" by Fritz Hahn, 1964. This is the most detailed rotisserie cake lineage that you could ever hope for.
Excerpt from Was zu 180 Zuckern Leckkuchleinn von Wirtz und Zucker genomen wirt, a.k.a. Was zu 180 Zuckern Leckküchlein von Wirtz und Zucker genomen wirt, a.k.a. How to make 180 sweet and tasty cakes with spice and sugar. Written by Susanna Harsdörfer, Nuremberg, 1582. This may be the earliest spit cake recipe to feature layered batter.
Excerpt from En Nödig och Nyttig Hus-Hålds och Kok-Bok, a.k.a. A Necessary and Useful House- and Cook-book. Written by Susanna Egerin, Stockholm, 1737. Perhaps the earliest printed recipe for the unique spettekaka of south Sweden.
Excerpt from Ein new Kochbuch, a famous text for aristocrats' chefs. Written by Marx Rumpolt, Mainz, 1581. An influential (but certainly not the earliest) recipe for chimney cake, possibly of the baumstriezel style.