Mystery Vegetable

Our local fresh delivery co. brought this veggie that looks like a bushy green spider to our house today.  Yes, what you see is really all one...one of whatever it is.

Thankfully, the veggies come with literature that labels them.  If not, I'm not sure how I would ever figure out that this is tatsoi.  At this moment, I still have no idea how to cook it but I may try to do so tomorrow.  So if you have any suggestions or ideas, please leave a comment!