Preheat oven to 400°F (200°C).
Line a baking sheet with parchment paper. Add cherry tomatoes, chopped onion, salt and olive oil and toss until the veggies are evenly coated.
2 lb cherry tomatoes, 1 yellow onion, 1 teaspoon salt, 2 tablespoon extra virgin olive oil to drizzle
Add the garlic. Transfer to the oven and roast for 40 minutes on the middle rack or until the tomatoes are soft and slightly charred.
4 garlic cloves (skin on, top chopped off)
Remove veggies from the oven and allow to cool slightly. Peel the garlic and add it together with the roasted tomatoes and onion (and their released liquid) to a high-speed blender. Add the coconut milk, vegetable broth and fresh basil and blend until smooth. Alternatively, you could add the ingredients to a small saucepan and blend with an immersion blender.
¼ cup vegetable broth, ½ cup unsweetened coconut milk (optional, see notes), 1 small handful of fresh basil
Serve immediately or if the soup isn't hot enough anymore, transfer the blended soup to a small saucepan and bring to a gentle simmer.
Taste and adjust seasoning. If the soup is too thick, add a splash of broth or coconut milk. If your veggie broth wasn't salted you might need to add more salt.
Optional Toasted Bread Step: I like to brush a couple of slices of white bread (sourdough or ciabatta) with olive oil and add it to the veggies in the oven for the last 10 minutes.
Top with black pepper and fresh basil and serve with crusty bread on the side.