The key to this dish is to roast the vegetables in batches. If you roast all at once, the temperature in the oven will drop, then they will sweat and not roast correctly. The sauce must be thick enough to coat the vegetables but not too thick.
I think this dish is best left overnight and re-warmed, great as a starter or a main course. If I had vegetable dishes like this as a child it would have been fantastic…
Other serving ideas: