I think she might just be trying you on! I know it's not easy, but you might just have to try following through on the "that's all you are getting threat". It might just be a phase. She might also not be that hungry at night. I know my DS1 can eat a horse for breakfast, but he's a bit of a grazer for the rest of the day. We battled to get him to eat dinner - and he won the battle by not eating. We gave up battling, and when he's hungry he'll eat, but when he's not, he's not going to starve.
Do limit milk intake. That's what my 2 years old would do, fill up on milk.