One of my favorite things to do with a mix of summer vegetables is to slow-roast them, drizzle with olive oil and eat with slices of toasted bread. A Spanish restaurant I used to go to had a similar dish called "Escalavida," which they sadly took off the menu. I used bell peppers, zucchini, tomatoes and onions, but eggplant is also a great addition. I did each vegetable under the broiler separately, but a grill is even better if you have one!
Bell Peppers: Arrange peppers on a foil-lined baking sheet. Adjust oven rack so the peppers can sit as close to the broiler heating element as possible without touching it. Preheat broiler and put in peppers. Watch and turn when the skin facing the broiler turns black (you'll begin to smell at about the same time). Turn until most of the skin is black and peeling (they don't have to be totally black...about 75%). Cool in a Ziploc bag or a bowl, until they're cool enough to handle.
The skin should then fall off pretty easily. Resist the urge to rinse them- it will be faster and you'll get rid of all the black but they won't have that wonderful roasted, caramelized, smokey taste.
Eggplant: Position rack so that eggplant will be a few inches from the broiler. Rotate the eggplant periodically so the skin is charred and pulls away. Let the eggplant rest until cool enough to handle. Cut open and pull out the inside in strips. Taste some- if it's still a bit chewy, throw it back in for a few more minutes.
Tomatoes: Cut tomatoes in half on the equator and seed. If they're large, cut into quarters. Let them drain for a few minutes on paper towels. Arrange on a rimmed baking sheet (not too crowded- an inch or so between pieces) and drizzle with olive oil and sprinkle with salt. Roast a few inches under the broiler for about 5-10 minutes to cook out some of the water and just begin to brown the edges. (These aren't so well-suited to the grill as the other veggies)
Onions: Cut onions in half, and then into wedges about 1 inch thick. Toss with olive oil and salt and arrange on a rimmed baking sheet. Roast a few inches from the broiler, stirring when the edges start to brown. Take them out when the onions are translucent and browned on the edges. (On the grill- Cut the onions in slices like you would for onion rings. Use a toothpick to hold all of the rings together. Grill on medium-high heat. These make burgers amazing.)
Zucchini and Summer Squash: Cut lengthwise into quarters or smaller. Toss with olive oil and salt and roast several inches under the broiler, turning periodically so no sides get too brown.
Arrange on a dish and drizzle with a good olive oil. Slice bread, brush with olive oil and arrange on baking sheet. Put the sheet in the still-warm oven (broiler turned off) to lightly toast.
I found these adorable baby zebra eggplants, a pint of small roma tomatoes, and a few small zucchinni and a bunch of green onions (all of which cost, like $6. Seriously). The cool thing about ratatouille is that you can play with the proportions of stuff, add a bell pepper, or not, substitute cherry tomatoes for big ones, or yellow squash for zucchinni, a different kind of onion... It's a completely foolproof and intuitive dish- in a Dutch oven sautee onions and pepper if using, add cut up eggplant, cook for a bit, add zucchini, cook till tender, stir in cut up tomatoes and season. Most recipes I've seen just call for fresh thyme, which is all you need, but it's also great with a few big teaspoons of herbs de provence and a generous pour of balsamic vinegar.
