Agree with the dipping idea, DD loves pumpkin soup or lentil soup coz she loves dipping bread into it.
Corn on the cob?
Does he eat rice? Coz if you cook meals that have stuff that dissolves like eggplant, you can mix it into the rice and they don't tend to notice there's a veg in there.
DD loves eggs, hard boiled and also scrambled eggs.
Sausages?