The vegetables for this dish are grilled from raw. They aren’t parboiled in advance. The sort of overhead grill most cookers have, which chefs know as a salamander, does not cook this dish properly. If you have a barbecue set in the garden shed, that would be perfect.
These grilled vegetables make a good first course. You would need to avoid duplicating the ingredients in your main course, naturally. Maybe give a tossed salad instead. The dish, without the tomato sauce, will partner