01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Place halved tomatoes, onion, garlic, and carrot on the prepared baking sheet. Drizzle with olive oil and season with 1/2 tsp salt and black pepper.
03 - Roast vegetables for 25-30 minutes until tomatoes are soft and edges are caramelized.
04 - In a large pot, melt butter over medium heat. Add roasted vegetables, dried basil, thyme, and red pepper flakes. Stir constantly for 2 minutes to blend flavors.
05 - Pour in vegetable broth and bring to a boil. Reduce heat to low and simmer for 10 minutes.
06 - Using an immersion blender, puree the soup until completely smooth. If using a countertop blender, work in batches and carefully transfer hot soup.
07 - Stir in heavy cream until fully incorporated. Taste and adjust seasoning with remaining salt if needed.
08 - Ladle hot soup into bowls and garnish with fresh basil leaves and a swirl of cream if desired.