Preheat oven to 400°F (200°C).

Cut tomatoes and onion into wedges. Peel and smash garlic cloves.

Toss tomatoes, onion, and garlic with olive oil, salt, and pepper on a baking sheet.

Roast for 30-40 minutes, or until tomatoes are softened and slightly caramelized.

Transfer roasted vegetables to a blender or food processor.

Add vegetable broth and blend until smooth.

Heat soup in a pot over medium heat. Adjust seasoning to taste.