I understand not wanting to throw food away, but I see absolutely no reason to force a child to eat something they either don't like (and I don't mean not prefer that day - I'm talking about something they truly don't like), or that they aren't hungry for (i.e. they're full.) Neither makes sense to me. The only case I can see for either of these is if your family is impoverished, and forced to eat certain items because of availability to you, which I doubt is the case.
I do not believe in creating food/eating battles. In the culture in which we live, eating disorders are so common, I have no desires to do anything to assist in creating one in my kids, by micromanaging what they eat.
My son has a VERY sensitive gag reflex, has since he was very young, so does his father, grandmother, etc. He is willing to try new things, but if he doesn't like the taste or texture of something, he will gag, which usually results in him vomiting. I have learned that if he says he doesn't like something, I don't push it with him. In fact, last evening, we had tacos, with a new kind of taco cheese. He took one bite, motioned to me that he couldn't swallow it, went to the garbage can and puked. And I was ok with that. He tried it. He couldn't eat it.
If this is truly about wasting food, a PERFECT solution is to have your daughter's uneaten food in your husbands lunch the next day.
If your husband thinks it's about stubbornness, I'd be curious to know if he regularly chooses to eat entire portions of food that he doesn't like. Having your daughter eat everything that's placed in front of her despite her own physical cues teaches her to ignore her brain and body, and eat more than she physically needs. That leads to overeating and an inability to navigate portion size on her own.
If your daughter chooses not to eat all of her dinner, I'd just make a standing rule that if she's hungry later, she can only have X, whatever you decide X to be, a slice of buttered bread, perhaps. That's a basic, no prep, not too exciting alternative, that will help fill her belly, if she's truly hungry. Or a piece of fruit, or some raw veggies. That way, there's no manipulation on her part involved, where she's refusing dinner so she can have snack Y in the evening. I'd tell her no snacks in place of dinner. If she chooses not to eat her dinner, she can only have X if she gets hungry.
That way, you are making it about choices, not a power struggle. Ahead of time, you have laid out the expectations, and the consequences. So in the moment, you can be very matter of fact about how you handle it if she chooses not to finish her dinner.