Sub for Palm Vinegar?

Saveur recipe for Chicken Adobo calls for this ingredient. Never heard of it and can’t find it. Any ideas?

I have a few Thai cookbooks that recommend brown sugar as substitute. I have found palm sugar in Asian markets but the one that I bought was so hard I had to use a grater to get some off. It does have a bit of a different taste than brown sugar but not different enough that it will make too much of a difference in a recipe that has several more ingredients. Perhaps I would feel differently if I had the opportunity to try a fresher batch of the palm sugar.

I had it before in the pantry but the last time I did a chicken adobo I used a blend of white and cider vinegar and really liked the flavor. It’s been a while but I don’t remember palm vinegar having a very distinctive flavor

Oops, sorry fired that as Palm sugar.

Thanks. I’ll try your white/cider blend.

I’ve been using white balsamic a lot lately; I think it might be a good sub for palm.