Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup.
Step 2: Wash and roughly chop your Roma tomatoes, red bell peppers, yellow bell pepper, and yellow onion. Peel and smash the garlic cloves.
Step 3: Arrange the chopped vegetables and garlic on the prepared baking sheet. Drizzle generously with olive oil, ensuring all vegetables are lightly coated. Season with a good pinch of salt and black pepper. Toss gently to combine.
Step 4: Roast the vegetables for 40-45 minutes, or until they are tender, slightly caramelized, and have some charred spots. This roasting step is key to developing the deep, sweet flavors.
Step 5: Carefully transfer the roasted vegetables, along with any pan juices, to a high-speed blender. Add the vegetable broth, fresh basil leaves, fresh oregano leaves, red wine vinegar, and the optional pinch of sugar.
Step 6: Blend until completely smooth and creamy. If you prefer a thinner consistency, you can add a little more vegetable broth, a tablespoon at a time, until desired thickness is reached.
Step 7: Taste the soup and adjust seasonings as needed. You might want a little more salt, pepper, or vinegar to brighten the flavors.
Step 8: Pour the blended soup into a clean container, cover tightly, and refrigerate for at least 4 hours, or preferably overnight, to allow the flavors to meld and the soup to become thoroughly chilled.
Step 9: Before serving, give the soup a good stir. Ladle into bowls and garnish with extra fresh basil leaves, a swirl of olive oil, or other desired toppings. Enjoy!