Bottles o' Enchanting are right now kind of useless because of how expensive they are. It would be beneficial to be able to craft them because then you could store XP for later enchanting, for example, before fighting a boss where you might die or lose your levels, or to be able to share/sell XP with other players.
Bottles o' Enchanting produce 3 to 11 XP when thrown, so for balance reasons they should take 11 XP to craft, similarly to how melons, etc. lose pieces when you craft, then mine them.
The crafting recipe would just be a glass bottle, shapeless, in the crafting grid.