Take the food away..period. If she is playing she isn't eating. Make sure it is clear why she is getting it taken away, "we do not throw food, I guess you are done" and get her down. This will help, it will take time but she will catch on she is to eat when she is in her highchair and play when she is not eating...
I say now is the perfect time to teach her how to eat and have manners so you can go out to eat or someone else's house without her trashing their house.
Yes it is a phase, but I would just nicely tell my kids, "I guess all done!" and put them down. My son after only two weeks figured it out quickly, he was my eater, hee hee.