Preheat your oven to 400°F (200°C). This high temperature will caramelize the natural sugars in the tomatoes, enhancing their flavor.

On a baking sheet, place the halved tomatoes cut-side up. Drizzle with olive oil and sprinkle with salt, pepper, and oregano.

Roast in the preheated oven for 25-30 minutes, or until the tomatoes are soft and slightly charred. This step adds depth to the soup.

In a large pot, heat a tablespoon of olive oil over medium heat. Add the diced onion and sauté for about 5 minutes until translucent. This will create a flavorful base for the soup.

Add the minced garlic and cook for an additional 1-2 minutes, stirring frequently to prevent burning.

Pour in the vegetable broth and bring to a simmer. Once the tomatoes are roasted, add them to the pot along with any juices from the baking sheet.

Using an immersion blender, blend the soup until smooth. If using a regular blender, allow the soup to cool slightly before blending in batches to avoid splattering.

Stir in the heavy cream, balsamic vinegar, and sugar. Taste and adjust seasoning with salt and pepper as needed. The cream adds richness, while the vinegar and sugar balance the flavors.

Serve hot, garnished with fresh basil. Enjoy your homemade roasted tomato soup with crusty bread or grilled cheese for a complete meal!