Preheat the oven to 400°F. Line a large sheet pan with parchment paper or foil.
Arrange the tomatoes, carrots, red bell pepper, onion, and unpeeled garlic cloves on the prepared sheet pan. Drizzle with olive oil, sprinkle with salt and black pepper, and toss to coat.
Roast for 25–30 minutes, or until the vegetables are tender and the carrots are easily pierced with a fork.
Allow the vegetables to cool slightly. Remove the garlic and onion skins, then transfer the vegetables to a blender and blend until smooth.
Transfer the blended vegetables to a saucepan. Stir in the vegetable broth, chili powder, Italian seasoning, and sugar. Heat over medium heat for 5 minutes, stirring occasionally.
Reduce the heat and stir in the heavy cream. Serve warm with Parmesan cheese and toasted bread, if desired.
Notes
For a thinner soup, add additional vegetable broth until it reaches your preferred consistency.
A countertop blender will produce a smoother consistency, but an immersion blender also works.
Store leftovers in an airtight container in the refrigerator for up to 3–4 days. Reheat gently, stirring occasionally.