Battle of Wills

I have posted before about my darling picky eater, who hardly eats anything, and the things that she will eat are few and far between. Her picky/lack of eating is worse some weeks, better on others. This week has been one of those bad weeks for Emmy's appetite. She has hardly eaten anything the past few days, and it makes meals so stressful for me - every other sentence out of my mouth is "Emmy, eat your (insert food here)" or "Emmy, sit back down, you only ate 2 bites". It is SO frustrating.
Tonight, I made beef stroganoff (from a box, of course), which we all like. Emmy started to eat, said it was yummy, then 3 noodles later said she was full. Which then began the battle. The only way I could get her to eat was if I fed her - which I am not going to do, she is definitely big enough to feed herself.
After a while, she kept getting up from her chair, I kept hollering at her to sit and eat, and eventually I put her in the highchair to keep her sitting. She looked ridiculous sitting in the high chair. I told her she was not getting down until the food was gone - she only had about 4 bites left.
She refused to eat. She cried. She fussed. She whined. She said I was hurting her feelings. She said she was too full to eat.
I ignored her, other than occasionally reminding her that she was not getting down until the plate was empty.

An hour and a half later, she was still sitting there. Despite my better judgment, I fed her the last 4 bites and got her down, since was now 7:00 and she still needed a bath.
How did she get so stubborn?? It must be from her Dad...
She is driving me bananas.