I don't have a "recipe"....but I can guide you in winging it.
But you will need some onion, garlic, tomatoes, peppers and cheese of one sort or another....
My thoughts are to sautee that stuff in olive oil until just crisp tender, pop it into a gratin dish....top with cheese and crutons tossed together....and perhaps drizzled with a bit of , as Rachael Ray would say "EVOO". ( My she is annoying!) And bake for about 30 minutes at 350.
Linda C

Or......... you could cut the zucchini lengthwise, scoop some of the insides out and use the croutons as a stuffing (zap in food processor with a little onion or garlic, parsley and olive oil) top with cheese and bake them.

I don't understand; how does a crouton go stale? It's just stale bread to begin with.

At any rate, worse comes to worse, put them in a zip lock and run your rolling pin over them a couple of times to make bread crumbs, which you can then use as a topping.

I have a whole full jar of breadcrumbs that I rarely use. Croutons are dried out bread, now with the humidity they've gotten soggy, which was my conception of stale, although to be precise soggy is the better term. Croutons go soggy and stale all the time. And nothing is worse than soggy stale bread. Unless you are making stuffing.

Linda I sort of followed your recipe. It tasted very yummy but I wasn't crazy about the texture, it seemed soggy to me. I just do not have the knack with stuffing. Well, it got all ate up so I must have done something right. If I make this again I think I'll leave out the tomatoes, or boil out more liquid from the veggies in advance, and perhaps bake longer. I was rushed. I added two eggs to make it more like a bread souffle. I can rarely manage to get stuffing right, it is always my worst dish at Thanksgiving time. It's either soggy or too dry.