Preheat oven to 430°F | 220°C. Place tomatoes on a baking tray with the garlic cloves. Drizzle with 2 tablespoons of oil, season with salt and pepper, and roast for about 25 minutes, or until soft and charred on the tops.
While tomatoes are roasting, heat 1 tablespoon of oil in a medium-sized pot/saucepan over medium-high heat. Add the onion, peppers (capsicum) and potato; cook while occasionally stirring, until the onion is transparent and the potato begin to crisp on the outer edges (about 6-7 minutes). Stir the tomato paste through the potatoes and onion; pour in the broth/stock; season with extra salt; cover and bring to a boil.
Reduce heat to low; simmer for about 15 minutes or until potato is just tender when tested with a fork. Add the tomatoes, garlic and basil to the broth (save 2 tablespoons of basil to use as garnish if you wish); continue to simmer until the basil is just soft (about 2 minutes). Blend soup using a stick blender until smooth.
Pour the soup through a strainer or colander to remove any skins and thick tomato pieces, for a smoother soup.
Sprinkle with extra basil, shaved parmesan cheese, and serve with cheesy garlic bread