Preheat your oven to 425°F (220°C). Place the halved red bell peppers skin-side up on a baking sheet and drizzle with 1 tablespoon of olive oil.
Roast the peppers in the preheated oven for about 25-30 minutes or until the skins are charred and blistered. Remove from the oven and let them cool slightly before peeling off the skins.
In a large pot, heat the remaining tablespoon of olive oil over medium heat. Add the diced onion and sauté until it becomes translucent, about 5-7 minutes.
Stir in the minced garlic and cook for an additional 1 minute until fragrant.
Add the roasted bell peppers, chopped tomatoes, vegetable broth, sugar, dried basil, salt, and pepper to the pot. Bring to a simmer and cook for about 15-20 minutes.
Using an immersion blender or a regular blender (in batches if necessary), blend the soup until smooth and creamy.
Return the soup to low heat and stir in the heavy cream or coconut cream. Adjust seasoning if necessary.
Allow the soup to warm through and serve hot, garnished with fresh basil leaves.