Hi, Hmmm, Never heard of Trader Joes?
Perhaps I'll do a web-search, and see what I come up with?

The Pickled Mushrooms for Martinis, that I have been buying are
absolutely killer! They come in regular, garlic, and various "heat"
ranges.

They are from Shrooms Kitchen at River Valley Ranch in Burlington,
Wisconsin.
Web address I just found is:
www.shroomskitchen.com

If I could make them like this, I'd be a very happy man! Mark