You might not think "summer" and "stew" belong in the same sentence, but stewing and braising aren't winter-exclusive cooking methods. The colorful spectrum of summer vegetables can be slow-cooked until meltingly tender and sweet — and it's quite easy to do with the help of a slow cooker. Ratatouille, the classic French vegetable stew, is a perfect candidate for this hands-off cooking method.
Slow Cooker Ratatouille: Watch the Video
When I'm using a slow cooker, I like to keep things simple, so all the vegetables get chopped and thrown right in together. There's one exception: I cook the onions on the stovetop first until they soften and begin to brown. The precooked onions really add a deeper layer of flavor to this simple vegetable stew. You might think that cooking onions on the stove will take up more cooking time than you'd like to spend, but they cooked in about the same amount of time as it took me to trim and cut the rest of the vegetables. All I had to do was give them a stir every once in a while.
The rest of the vegetables in this ratatouille scream summer: eggplant, summer squash, bell peppers, tomatoes, and lots of garlic slow-cooked until meltingly tender. Stir in some fresh basil at the end and you've got a vegan side dish that's great served with grilled proteins, spooned onto toasted bread, or even tossed with freshly cooked pasta for an easy summer meal.
4 tablespoons olive oil, divided, plus more for drizzling
2 medium yellow onions, diced
1 pound eggplant
1 pound zucchini or summer squash
2 large red, green, or yellow bell peppers (about 1 pound)
1 pound tomatoes
4 cloves garlic
2 tablespoons tomato paste
1/2 teaspoon fine salt, plus more for seasoning
1/4 cup coarsely chopped fresh basil leaves
Heat 2 tablespoons of the oil in a large frying pan over medium heat until shimmering. Add the onions, season with salt, and cook, stirring occasionally and adjusting the heat as needed, until completely softened and light golden-brown, about 30 minutes. Meanwhile, prepare the rest of the vegetables.
Trim the eggplant and zucchini, cut into 1-inch cubes, and place in the insert of a 6-quart or larger slow cooker. Trim, core, and cut the bell peppers into 1-inch dice and add to the slow cooker. Core the tomatoes, cut into 1 1/2-inch dice, and add to the slow cooker. Finely chop the garlic and add to the slow cooker.
When the onions are ready, add the tomato paste to the pan and stir to coat the onions. Transfer the onion mixture to the slow cooker. Add the remaining 2 tablespoons oil and 1/2 teaspoon salt. Stir to coat all the vegetables.
Cover the slow cooker and cook until the vegetables are extremely tender, 4 hours on high or 5 to 6 hours on low. If you'd like to cook off some of the excess liquid in the slow cooker, cook uncovered for the last 30 minutes.
Stir in the basil and taste for seasoning, adding more salt as needed. Drizzle with more olive oil before serving if desired.
- Storage: The ratatouille can be stored in an airtight container in the refrigerator for up to 5 days.