Name for a flour-free onion sauce
A soubise is a classic french onion-based sauce.  Really it is just slow cooked onions with a bechamel added.  Of course, bechamel has flour in it to thicken.  However, I have seen recipes where the bechamel is replaced with heavy cream.  For example, here, onion, cream, and vadouvan spice are blended together to make a flour-free soubise.  It would make a terrific pot pie filling!