Sauté the Aromatics: Heat olive oil in a large pot over medium heat. Add the chopped onion and sauté for 4-5 minutes until soft and translucent. Add the garlic and cook for another 1 minute until fragrant.

Cook the Base: Add the canned tomatoes (with their juice) or fresh tomatoes, vegetable broth, oregano, red pepper flakes (if using), and sugar. Stir to combine, breaking up the tomatoes with a spoon if using whole ones. Bring to a simmer and cook for 10 minutes, stirring occasionally.

Blend the Soup: Add the fresh basil leaves to the pot. Using an immersion blender, blend the soup until smooth. Alternatively, carefully transfer the soup to a blender in batches and blend until smooth, then return to the pot.

Add Creaminess: Stir in the heavy cream (or coconut cream) and simmer for another 5 minutes to heat through. Taste and adjust seasoning with salt and black pepper as needed.

Serve: Ladle the soup into bowls, garnish with fresh basil leaves, and serve hot. Pair with crusty bread or a grilled cheese sandwich for a comforting meal.