This vegetable stew has been around for ages, yet feels as contemporary now as ever before. Though it’s usually served hot as an accompaniment to a main protein, I love ratatouille cold, topped with a poached egg, as a refreshing main course in the summer when Provençal vegetables are at the height of seasonality.
I prefer to make this in a wide, heavy pot to allow for maximum evaporation and consolidation of flavor. Never let the stew sit on a boil; simmer it gently to ensure the vegetables maintain their shape. The extra step of reducing the vegetables’ juices is well worth the added few minutes. If you have a big enough pot, double the recipe, as this keeps well for several days. In fact, this is one of those dishes that will taste better on the second day.
For the vegetables to cook at a similar rate, they must be cut to about the same size.
Using the quartered onions as a reference point, prepare the bell peppers.
Discard their stems and seeds, cut in half lengthwise, then cut again lengthwise to match the size of the onions.
The same applies to the zucchini and eggplant.
Discard the ends, cut in half lengthwise, and cut to match the size of the onions, leaving the seeds in.
Set aside in separate piles, as you’ll cook them separately.
Cut the tomatoes in half horizontally.
Squeeze their seeds out over the sink to discard and coarsely chop the remaining flesh.
Set aside.
In a large pot on medium heat, combine the onions and ¼ cup of the olive oil, and sauté, stirring occasionally, so they soften but don’t brown, about 10 minutes.
Add the bell peppers, garlic, a pinch of espelette pepper, and a large pinch of salt.
Continue to cook until the bell peppers have softened.
Transfer the onion and pepper mixture to a large bowl and set aside.
With the pot still on medium heat, stir together ¼ cup of the olive oil and the eggplant.
Cook, stirring occasionally, until the eggplant begins to take on some color, about 2 minutes.
Add the zucchini and cook until softened, about 4 minutes.
Return the onion and pepper mixture to the pot and stir in the tomatoes and thyme until combined.
At this point, the tomatoes will expel their water and the mixture will resemble a soup.
Increase the heat until the liquid comes to a gentle boil, stirring occasionally to prevent sticking, then turn the heat to low and cover your pot with the lid slightly ajar to allow steam to escape.
Simmer, stirring occasionally, until the vegetables are cooked through but maintain their shape, 1 to 1½ hours.
Be careful to stir gently so as not to break up the vegetables.
Set a colander over a large bowl.
Carefully transfer the entire contents of the pot into the colander, reserving both the vegetables and their juices.
Return the juices to the pot.
Stir in the tomato paste and turn the heat to high.
Bring the liquid to a boil, stirring often, until it has a thick and syrupy texture, 3 to 5 minutes.
Remove the pot from the heat and gently stir in the vegetables, parsley, basil, and the remaining ¼ cup olive oil, being careful not to break up the vegetables.
Add salt and black pepper to taste.
Serve immediately on its own or topped with a poached egg, or chill the ratatouille thoroughly in your refrigerator before serving.
Stored in an airtight container, the stew will keep in your refrigerator for up to 4 days.