Roast the Tomatoes Preheat oven to 400°F (200°C). Halve tomatoes and place cut-side up on a baking sheet with chopped onions and garlic cloves (unpeeled). Drizzle with olive oil, sprinkle salt and pepper, and roast for 30 minutes until soft and caramelized.
Sauté Aromatics In a heavy-bottomed pot, heat 1 tbsp olive oil over medium heat. Squeeze roasted garlic out of skins and sauté briefly with a few basil stems and thyme. Add roasted tomatoes and onions. Stir and simmer for 5 minutes.
Deglaze & Blend Pour in vegetable broth. Simmer uncovered for another 10 minutes. Remove basil stems. Use an immersion blender (or transfer carefully to a high-speed blender) to blend until smooth.
Adjust Seasoning & Serve Return soup to the pot. Add torn fresh basil leaves and stir. Taste for salt, pepper, and sugar if needed. Serve hot, drizzled with olive oil or crème fraîche.
