One-Pan Mediterranean Vegetable Ratatouille

By Lauren Mitchell, Test Kitchen Director · Reviewed by AislePrompt Editorial · Published 2026-07-01 · Updated 2026-07-01

A vibrant medley of zucchini, eggplant, bell peppers, and tomatoes slowly cooked in a single pan with aromatic herbs. This mediterranean-inspired vegetarian (gluten free) ready in about 50 minutes pairs olive oil, medium, diced yellow onion, minced garlic cloves for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 150 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 3 tbsp olive oil
• 1 medium, diced yellow onion
• 4 cloves, minced garlic cloves
• 1 medium (about 1 lb), diced into 1-inch cubes eggplant
• 2 medium, diced into 1-inch cubes zucchini
• 1 large, diced red bell pepper
• 1 large, diced yellow bell pepper
• 14 oz can, with juice canned diced tomatoes
• 1 tbsp, chopped fresh thyme
• 1/4 cup, chopped fresh basil
• 1 tsp salt
• 1/2 tsp black pepper
• 1/4 tsp, optional red pepper flakes

Instructions

1. Step 1: Heat 3 tbsp olive oil in a large deep pan over medium heat until shimmering. Add 1 diced medium yellow onion and sauté for 4-5 minutes until translucent.
2. Step 2: Add 4 minced garlic cloves and cook for 1 minute until fragrant, stirring constantly.
3. Step 3: Add 1 medium diced eggplant (about 1 lb) and cook for 6-7 minutes, stirring occasionally, until softened and edges start to brown.
4. Step 4: Stir in 2 diced medium zucchinis, 1 large diced red bell pepper, and 1 large diced yellow bell pepper. Cook for 5 minutes until vegetables begin to soften.
5. Step 5: Pour in 14 oz canned diced tomatoes with their juice, then add 1 tbsp chopped fresh thyme, 1 tsp salt, 1/2 tsp black pepper, and 1/4 tsp red pepper flakes if using. Stir gently.
6. Step 6: Reduce heat to low, cover the pan, and simmer for 15 minutes until all vegetables are tender and flavors meld.
7. Step 7: Remove from heat and stir in 1/4 cup chopped fresh basil before serving warm.