I can get my 19mo to eat more vege if it is mixed with pasta and with a cheese/white sauce. I also add some chicken this way too and he will eat it. You could try making patties/croquettes and adding the vege that way - this has also worked for us. If I serve up meat and vege on a plate, he will only eat the meat, plus maybe a few peas and carrots. One thing he really does like is the rafferty's veges in the squeezie packs as I don't think he realises they are vege LOL - I think he thinks they are the fruit ones which he loves.

Another thing too is that my DS is more receptive to eating a bigger meal at lunchtime, so often he will have his main meal at lunch and then only a light supper before bed. that might be something you can try too.