Preheat your oven to 450°F (232°C). Cut the Campari tomatoes in half and place them in a large baking dish alongside the sliced onion and unpeeled garlic cloves. Drizzle generously with olive oil, then season with kosher salt, oregano, and smoked paprika. Roast everything for 30 to 40 minutes until the tomatoes are caramelized and the onion is tender, stirring halfway to ensure even cooking.

Once the roasted vegetables have cooled slightly, transfer them to a large pot. Add a handful of fresh basil leaves for an herby punch. Using an immersion blender, blend the mixture until smooth and velvety. If you prefer a chunkier texture, you can also blend in batches using a standard blender, ensuring to let the mixture cool to avoid splatter.

Stir in the vegetable broth and heavy cream to achieve your desired consistency for the roasted tomato soup. Allow it to simmer gently over medium heat for about 5 minutes while stirring occasionally. Taste and adjust seasoning, adding more salt to your preference or a spoonful of sugar to balance any acidity from the tomatoes.

Ladle your warm, velvety roasted tomato soup into bowls. To elevate the experience, garnish with additional chopped fresh basil, creating a burst of color and flavor. Pair this delightful soup with a crispy grilled cheese sandwich or a simple side salad for a cozy and satisfying meal.