This is good warm or cold so it’s a great for Yom Tov. The orange zest gives the soup a great flavor boost and makes it interesting.
Nonstick vegetable oil spray
1-1/2 pounds red bell peppers (about 3 large), quartered, seeded
1 large yellow bell pepper, quartered, seeded
1 pound plum tomatoes, trimmed, quartered
1 cup sliced onion
3 garlic cloves, thinly sliced
2 tablespoons olive oil
1-3/4 cups (or more) low-salt chicken broth, divided
3 tablespoons chopped fresh basil, divided
1 teaspoon grated orange zest
Preheat oven to 425°F. Spray large rimmed baking sheet with nonstick spray. Arrange all bell peppers and tomatoes on prepared sheet, cut side up. Scatter onion and garlic over. Drizzle olive oil over vegetables; sprinkle with salt and pepper. Roast until peppers are soft and beginning to brown around edges, turning occasionally, about 1 hour. Remove from oven. Enclose yellow pepper in paper bag 10 minutes, then peel and finely chop. Reserve for garnish.
Transfer half of remaining roasted vegetable mixture, 1 cup broth, 1 tablespoon basil, and orange peel to blender and puree until smooth. Transfer to large saucepan. Puree remaining vegetable mixture and 3/4 cup broth in blender until smooth. Transfer to same saucepan. Thin soup with additional broth, if desired. Season to taste with salt and pepper. DO AHEAD: Can be prepared 1 day ahead. Cover and refrigerate.
Rewarm soup over medium heat, if desired. Ladle hot or chilled soup into 4 bowls. Sprinkle with reserved chopped yellow pepper and remaining 2 tablespoons basil and serve.