Heat the oven to 400°F/200°C (convection).

Quarter the tomatoes and onions and spread them on a rimmed baking sheet. Slice the bell pepper into strips and add to the pan.

Cut the top off the garlic head, place on a piece of foil, drizzle with olive oil and a pinch of salt, wrap tightly, and add to the pan.

Drizzle the vegetables with olive oil, season with salt and pepper, and roast for about 1 hour, until the tomatoes are soft and beginning to caramelize.

Remove from the oven and carefully squeeze the roasted garlic from its skins. Transfer all the vegetables to a large pot. Add the boiling water and bring to a simmer.

Remove from the heat and puree with an immersion blender until smooth or to your preferred texture. Stir in the sugar and coconut cream or heavy cream, blending again until incorporated.

Return to a gentle simmer, adjust the seasoning, and stir in the basil just before serving.

Serve hot with toasted bread or croutons.