I have this problem with Kimberley and have learnt not to stress about it so much.
Some nights she doesn't touch anything on her plate and others she'll get a more. She hates veg other than carrots at the moment before i cook them as she likes the sound.
I've banned biscuits in the house as i found they where snacking on them nearly all day and wouldn't eat at night. It's worked a little and she does eat a bit more.

Last night all she had off her plate was two bits of lamb and mint jelly.

Alex on the other hand will eat nearly all his dinner and he's another one that isn't keen on veg. The only one that is at the moment is Eleanor but that could change.

I think they all go through this not eating stage and only wanting to eat certain things.

A few weeks ago it was jam sandwiches and before that it was chocolate spread so i stopped buying that.

When i ask what she wants for dinner she always asks for chips and that isn't going to happen every night.

What about getting your DS help you prepare the meal at night and see if that helps a little.
Kimberley loves to help and that is why she now eats raw carrot. I'm trying other veg but it doesn't make the same sound which is a same but maybe one day she will try it.