This recipe is a beautiful display of colors, as we can see from Alain Passard's collage. This recipe uses butter to assert itself in the flavors of the dish, and using cooked and uncooked ingredients, it's a play on both flavors and texture.
Recipe adapted from The Art of Cooking with Vegetables by Alain Passard, published by Frances Lincoln.
In a large sauté pan — preferably with flared sides — sweat the onion in 2/3 of the butter over very gentle heat until it softens slightly. Add 1/2 the quantity of the tomatoes, the garlic, and the zucchini cut into batons. Partially cover the pan with a lid and leave the ingredients to stew very gently for about 40 minutes, or until the watery juices from the tomatoes have evaporated.
Meanwhile, blister the skin of the peppers, as well as the eggplant, to make it easy to peel away their skin. The best way to do this is to skewer each vegetable whole and pass it through a naked flame from a gas hob or an open fire. If this is impractical, then use a regular grill. To make the blistered peppers easy to peel, wrap them briefly in a kitchen towel wrung out in cold water. Peel them, cut them into strips, and add them to the simmering ratatouille mixture.
When the eggplant is sufficiently blistered, leave it to cool for up to 30 minutes, then spoon out its flesh and put it in a saucepan along with the remaining butter. Stir to blend over low to medium heat until the pulp is lightly colored; season with salt and set aside in a warm place.
Prepare the uncooked ingredients for presentation: put the remaining tomatoes and zucchini in a salad bowl along with the basil. Dress the ingredients with the olive oil blended with a few drops of soy sauce to taste; set this aside at room temperature.
To serve, season the hot ratatouille with a few drops of soy sauce to taste, and transfer it to a large, warm serving dish. You can add the eggplant pulp to this dish or present it separately in a warm sauce boat. Offer the salad bowl of uncooked vegetables separately. Let diners help themselves and enjoy the elements of hot and cold.