This kind of sounds like a ratatouille lite recipe.
I made ratatouille last night, it is becoming one of my favorite side dishes. It is similar to this dish except you use:
zucchini, red onions, cherry tomatoes, bell peppers, garlic, eggplant (or in my case, I use mushrooms instead of eggplant, as I find eggplant competing with the zucchini). Cooking in stages, you low cook them for about an hour with some herbs de provence, and it comes out delicious...