Heat oil in a 10-inch skillet over medium-high heat. Add thinly sliced onions, thinly sliced zucchini, chopped red peppers, and salt. Cook for 8 minutes, stirring occasionally until the vegetables are slightly tender.
Stir in chopped tomatoes, minced garlic, Italian seasoning, salt, and pepper and cook, stirring occasionally, 3 minutes.
Transfer the ratatouille to a bowl or a plate and top with grated or shredded Parmesan cheese, if desired.
Notes
Fresh Produce: Always choose the freshest vegetables available for the best flavor.
Vegetable Variations: This versatile ratatouille recipe works well with different veggies. Substitute zucchini with summer squash or eggplant, and use any bell pepper color if red is unavailable.
Serving Suggestions: While great on its own, ratatouille also makes an excellent topping for grilled chicken or fish.