01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Arrange halved tomatoes, onion, garlic, and carrot on the prepared baking sheet. Drizzle with olive oil and sprinkle 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 for 2 minutes to combine flavors.
05 - Pour in vegetable broth. Bring to a boil, reduce heat, and simmer for 10 minutes to allow flavors to meld.
06 - Using an immersion blender, puree the soup until completely smooth. Alternatively, transfer to a countertop blender in batches and blend carefully.
07 - Stir in heavy cream. Taste and adjust seasoning with remaining salt if needed.
08 - Serve hot, garnished with fresh basil leaves and a swirl of cream if desired.