What would you buy as a thank you gift.

Z370Z011

So what would you guys buy as a "thank-you gift", for a 65 year old woman?
I recently met this lady at work and as I was telling her my career goals she mentioned her son is in the field I'm currently trying to get into. We couldn't have talked for more than 5 minutes and she completely vouched for me with her son, talking to him like if she's known me for years. He was immediately impressed with all the great things she said about me and has taken me under his wing to help teach me whatever he can. He was telling me that he normally doesn't do things like that but he was really impressed with the great feedback his mother had given him about me.
The reason for this post is because I'm extremely grateful that this lady did that for me without knowing me at all. So I just wanted to give her a small gift as a token of my appreciation but I'm TERRIBLE with gift ideas (DE. Knows how much I suck at it haha)

Any ideas?
Thanks in advance you guys