Add oil to a large saute pan and then add and cook the onion, celery, carrots and garlic over medium heat until softened (until a fork can be easily inserted into the carrots)

In the meantime, char the peppers under the broiler or on an outdoor grill until charred on all sides (rotate to blacken all sides) (see this post)

Place the charred peppers in a bowl covered tightly with plastic wrap or in a ziploc bag until cooled, then peel off skins

Add softened vegetables (carrot, celery, onion, garlic), canned tomatoes, peppers, basil, herbs and salt/pepper to blender and puree the mixture

Preheat oven to 280 degrees

Spread the puree on the bottom of an oven safe skillet or tart pan and then arrange the sliced eggplant, tomatoes and zucchini in a swirl fashion on top

Sprinkle with salt and pepper

Combine the olive oil, garlic and thyme and then drizzle on top of vegetables

Cover with aluminum foil and bake for 3 hours

At this point, it is recommended to refrigerate overnight to allow flavors to marry and mingle

To serve, heat oven to 350 degrees and bake uncovered for 45 minutes (if cold) or 20 minutes or warm/hot