Preheat the oven to 400F (204C). Slice the tomatoes in half, discarding the stems. Cube the onion and carrot. Add the tomatoes, onion, carrot and garlic cloves to a large roasting pan. Toss together with olive oil and half of the salt. Roast for 40 minutes, stirring halfway through.
Cool the vegetables for 10 minutes before transferring to a large pot. Add in the remaining ingredients. Use an immersion blender to puree until the soup is completely smooth. If you do not have an immersion blender, you can use a blender, but make sure your tomatoes are cool and you work in batches to avoid a mess! Simmer on low for 30 minutes before serving.
Top your bowl of soup with a garnish of fresh basil and Crackling Pork Belly Croutons.