Recently I had a very interesting comment made in regard to the origins of the Churros from Michael Krondl:
"I stumbled here quite by accident but a fortuitous one it seems since I know both Ken and Gary. Though as Ji says just because it happens to be made the same way doesn't necessarily prove anything but there are plenty of medieval Arab recipes that have you drizzle dough into hot fat. A pierced coconut is the favored utensil. The origin is likely Persian because of the name "zulabiya." Indian jalebi probably has the same origin. There's lots of Italian versions of this too. And for what it's worth the Acadamie Française dictionary traces pets de nonnes to the fourteenth century "pets d'Espagne." I'd put my money on the Arabic origin."
In response to this I originally replied that "...while I wouldn't discount the possibility of Moorish origins, but there is no proof. As I mentioned and as you expanded upon, there are Arabic batter fritters that are drizzled through holes into hot oil. These only superficially resemble churro et al, specifically they are not made from a hot water dough, which is important. Hot water dough doesn't drizzle well. Pushing a dough through a syringe is a different process to drizzling it though a sieve or pierced coconut..." I believe that this remains important point, churro and European syringed fritters are made using a very specific dough type that differentiates them from the very many other types of fritter, historical and extant.
When I originally wrote the article the earliest source I had found was 16th century Europe. During the period of the 16th to 17th century these fritters appear in many European countries, the early modern period was a fritter crazy time. On the other hand I could never find an Arabic version of this hot-water dough fritter.
However, I have recently read Nawal Nasrallah's translation of Ibn Sayyar al-Warraq's Tenth-century Baghdadi Cookbook, published as "Annals of the Caliphs' Kitchens". In this text while there are recipes for Zalabiya Mushabbaka (Latticed Fritters) that Michael mentions above, there is also one recipe for "Zalabiya Ghayr Mushabbaka" (un-latticed fritters). This recipe is for a hot-water dough fritter, albeit an unusual version. In this recipe the instruction is to cook flour in oil (make a Roux) and then add milk until it thickens. It you have made Béchamel sauce before then you will recognise this process. When the dough has cooled you form them into rings and fry them. Pets de nonnes with a hole.
So there is at least one early Arabic version of this fritter. However this still doesn't mean that this is the origin of Churros. This tenth century recipe doesn't appear in other medieval Arabic sources that I have access to (not an exhaustive list I must say), including the 13th century Anonymous Andalusian recipe collection . In short there is no continuity from this 10th century Arabic source to the hot-water dough fritters of the early European texts. There is also another issue in that the Roman recipe collection generally known as "Apicius" was a popular text in Medieval and Early Modern Europe also gives directions for making a hot-water dough fritter. In this instance flour/semolina is put into hot water until thickened (pultem), the cooled dough is then cut into suitable shapes and fried in oil.
Although the text of Apicius is from before the 10th century and thus has precedence to the Arabic source, it was also copies were made and traveled throughout Europe from the Medieval period onwards. In this respect the Apicius is the earliest European source, potentially, if highly speculative, even the source for later European recipes.
At this point I believe that while there is now evidence for very early production of hot-water fritters, there is still not enough evidence to connect these isolated recipes to the early modern hot-water fritters or the later developed Churro. It will be interesting to see how this research develops.
p.s. A further update, I recently came across the Turkish fried hotwater dough fritter "tulumba tatisi" ("pump sweet"), these are piped put of star nozzle, just like churro, and just like syringe fritters are named after the devise used to do this. In some instances "Tulumba" can also mean "syringe". Found throughout the Balkans. Although not Moorish this does shift the very specific cooking technique to the Eastern Med. and the Islamic sphere of influence. It will be very interesting to find out their origin in this part of the world.