Don't. It could be misconstrued as a come-on.
The best thing you can do is when you leave, post a nice review on a work website like Glassdoor or Indeed, and mention the "management" is great to work for.
That would reflect on her- and company HR reads those.
They are, on the other hand, funny about personal references, and that could reflect poorly on your relationship, and get her fired. Be careful. And no songs.