I made Ratatouille this weekend, and while I deviated considerably from the Julia Child recipe I was working from, it came out very delicious.
Here's roughly what I did:
Firstly, ingredient quality here seems to be paramount, so I bought all my vegetables at a farmer's market that day and prepared the Ratatouille immediately.
The first step was to cut the eggplant and zucchini into slivers (relatively thick, 1/3 inch or so) and toss them in a little bit of salt (not too much). Let them sit for about 30 minutes to draw out some of the moisture. You then want to array out a bunch of paper towels and let the veggies pat dry on them on both sides.
While your eggplant and zucchini are sitting in the salt, it'd be a good time to chop your onion (coarse), bell pepper (long strips are best, IMO), and to peel, de-seed, and juice your tomatoes.
For anyone who's never done it, the easiest way to peel tomatoes is to stick them in boiling water for 20 or so seconds and then peel from the bottom up. Skin comes right off. Then cut in half on equator and squeeze out all seeds and juice. Wash each piece if necessary under cold running water, you only want the "meat" of the tomato to remain. Cut each half into strips.
Once all the above mise en place is done, begin to saute your zucchini and eggplant in olive oil, adding more oil with each batch. Do the eggplant first and then the zucchini. Add nothing else to the pan. You want to brown them a tiny bit, but only do a minute or two per side, do not overcook.
Next up, in the same skillet, throw in some fresh smashed garlic and your onions and peppers. Salt and pepper minimally. Saute until tender, 10 mins or so, under med-low heat, do not brown. Add tomatoes and cover skillet while tomatoes render liquid.
Remove lid, baste everything in the liquid from the tomatoes, and then turn heat up to med-high to reduce off most of the remaining liquid.
Here's where I deviate most from your average Ratatouille recipe, from here on in...
Most people stack the vegetables in elaborate fashion in the casserole or pot (I used a pot, on the stove). I just mixed everything together, and I added fresh parsley, fresh basil, and a bay leaf.
Then I added.....wine. AFAIK no normal Ratatouille recipe calls for wine, but I cook the whole mess of everything together with some white wine (not a ton, but a cup or two) for 15 mins or so on med-high heat. The veggies should not be IMMERSED, it should just be an inch or two of wine in the bottom of your pot. Let it simmer for 15 or so mins covered and then remove the lid and let it reduce almost all the way down. Do not let the veggies on the bottom burn, toss things frequently, but a little browning down there isn't a bad thing, IMO.
Then, STOP. Remove pot from heat, allow to cool somewhat.
Take everything and spoon it into a casserole dish or something similar, anything oven-safe. Cover it with shrink-wrap and stick it in the fridge.
That's right, you don't get to eat it today. Ratatouille is always better reheated, so much so that I refuse to serve it the same day it's prepared.
When it comes time to reheat and serve, I like to let it warm up slowly with the oven. I set the oven to 250 and let the dish warm up as the oven preheats. I will then typically remove the dish, let the oven heat to BROIL, stick it back in, and let it get an ever-so-slight brownness to the top for all of a minute or two, then it's finally done.
A good Ratatouille is the star of the plate and will outshine all but the most flavorful meat dishes. Don't make it compete, serve it with something that may offer a nice texture contrast (i.e. something with a crunch or crisp) but not something with tons of flavor. A simple piece of seared Rockfish works great.
You can also toast ciabatta slices and serve the Ratatouille atop them, maybe with a little chevre.