Preheat your oven to 400 degrees Fahrenheit.

On a large baking sheet, spread out the halved tomatoes, quartered onion, and the head of garlic. Drizzle everything generously with olive oil and season with salt, black pepper, thyme, and rosemary.

Place the tray in the oven and roast for about 40 to 45 minutes. You are looking for the tomatoes to be collapsed and slightly charred on the edges. The onion should be translucent and caramelized.

Once cooled slightly, squeeze the roasted garlic cloves out of their skins. They will be soft like butter and perfectly sweet. Do not discard the juices from the roasting pan, they are liquid gold!

Transfer the roasted vegetables and all the pan juices into a high-speed blender or a large pot if using an immersion blender. Add the fresh basil and a portion of the vegetable broth.

Blend until smooth. Pour the blended mixture into a pot. If it is too thick, add more vegetable broth until you reach your desired consistency. Simmer for 10 minutes to let the flavors meld.

Taste for seasoning. Sometimes a squeeze of lemon juice or a pinch of paprika can brighten the whole pot. If you are not keeping it vegan, a sprinkle of parmesan cheese is a beautiful touch.

If desired, stir in the heavy cream for a creamy texture.