This the easiest and the best way I know to make the summery Provençal vegetable stew. All the vegetables go into an enameled iron Dutch oven at the same time along with some garlic, olive oil, and salt, and emerge from the oven 2 hours later perfectly cooked.

Makes about 8 cups

1 large white or yellow onion, about 12 ounces

2 light purple Japanese eggplant, about 8 ounces

2 thin zucchini, about 8 ounces

1 green or red bell pepper, about 8 ounces

1 ripe tomato, about 8 ounces (or more plum tomatoes in season, about a pound)

6 cloves garlic, crushed, peeled, and coarsely chopped

1/2 8-ounce can tomato sauce (not if using the pound of plum tomatoes)

1/3 cup olive oil

Salt

1 large sprig basil for cooking and more shredded or torn basil for serving

One enameled iron Dutch oven, about 4-quart capacity

Set a rack in the lower third of the oven and preheat to 350 degrees.
Peel, halve and dice the onion about 3/4-inch.
Rinse the other vegetables and tip and tail the zucchini and eggplant, and cut as for the onion. Cut the walls away from the pepper, trim away inside ribs and dice. Core the tomato and dice. (Halve plum tomatoes, remove seeds, dice.)
Combine all the vegetables with the garlic, tomato sauce, oil, and a good sprinkling of salt (not too much, the juices will reduce later), and use a wooden spoon to stir everything together; add a sprig of basil to the top.
Place the pan on medium heat and cook until the mixture starts to sizzle. Stir up and cook for about a minute longer.
Cover the pan and place it in the oven. Bake until the vegetables are tender but still fairly intact and the juices reduced, about 2 hours, stirring every 30 minutes. After 1 1/2 hours, taste for seasoning and add more salt if necessary.
Stir in about 1/4 cup shredded basil leaves and serve immediately. Or cool to room temperature, stir in the basil and serve.

Store the ratatouille in a covered container in the refrigerator. For advance preparation, cool and refrigerate, then bring to room temperature, add basil and serve.