Roasted Zucchini, Pepper and Red Onion Medley

By Lauren Mitchell, Test Kitchen Director · Reviewed by AislePrompt Editorial · Published 2026-04-02 · Updated 2026-04-02

A colorful sheet-pan of zucchini, bell peppers and red onion roasted in olive oil with oregano and garlic, served warm as a side or over grains. This mediterranean-inspired sheet pan (vegetarian) ready in about 37 minutes pairs zucchini, bell peppers, red onion for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 180 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

• 2 medium, sliced 1/2-inch thick zucchini
• 2, any color, sliced 1/2-inch thick bell peppers
• 1, thinly sliced red onion
• 3 tbsp olive oil
• 1 tsp dried oregano
• 1/2 tsp garlic powder
• 1/2 tsp salt
• 1/4 tsp black pepper
• 1 tbsp, chopped fresh rosemary

Instructions

1. Step 1: Preheat oven to 425°F (220°C). Toss 2 medium sliced zucchini, 2 sliced bell peppers, and 1 thinly sliced red onion with 3 tbsp olive oil, 1 tsp dried oregano, 1/2 tsp garlic powder, 1/2 tsp salt, and 1/4 tsp black pepper in a large bowl.
2. Step 2: Spread vegetables evenly on a parchment-lined sheet pan, ensuring they aren't overcrowded for even roasting.
3. Step 3: Roast for 20-22 minutes, stirring once halfway through, until edges are golden and vegetables are tender-crisp.
4. Step 4: Remove from oven, sprinkle with 1 tbsp chopped fresh rosemary, and toss gently to distribute. Let sit for 2 minutes to allow flavors to meld before serving.