It seems a bit weird that the sous chef isn't telling him the (likely) reason he's actually hiring him.
Ryuu chose to cook with the weird rare spices from the abode of humanity (isekai-japan), the guy takes interest in him because they have a banquet where they're about to serve someone from the abode of humanity. It seems like it would be a good idea to be like "hey, why did you choose those spices? Oh, you know a lot of recipes like that? That sounds interesting, let's talk about it with the rest of the staff a bit", but instead the chef just doesn't say anything about it.
I can only assume that instead, Ryuu's gonna surprise everyone with some japanese dish and save the day when things go south, and it'll just make me go "this could've been avoided in the first place if you actually talked to him about it at first, mr sous chef".