Preheat the oven to 400 degrees. Chop the eggplants, tomatoes, and bell peppers into 1 inch chunks. Throw them into a large, oven safe dish.
Cut the chives into small pieces and toss them in with the other vegetables. Whisk together the olive oil and vinegar then pour it over the vegetables. Add a big pinch of salt and pepper. Stir everything together.
Bake for 30 minutes, then stir. Bake another 30 minutes, or until all the vegetables are cooked through and the juices begin to thicken. Add fresh basil and parmesan right before serving. Enjoy!
If you want to save some ratatouille for later, it store great in the freezer. Put it in a sealable container and it keeps great. To heat back up, warm in an oven safe dish at 350 until warm, or in a pot over medium heat.