Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.

Roast the vegetables: Place the halved tomatoes, quartered onion, and garlic cloves on the prepared baking sheet. Drizzle with olive oil and season with salt and pepper. Roast for 25-30 minutes, or until the vegetables are tender and slightly charred.

Blend the soup: Transfer the roasted vegetables to a large pot. Add the vegetable broth, chopped basil, tomato paste, and sugar if using. Use an immersion blender to puree the mixture until smooth. Alternatively, blend in batches using a regular blender, then return to the pot.

Simmer the soup: Bring the soup to a simmer over medium heat. Stir in the heavy cream if using. Adjust seasoning with additional salt and pepper if needed. Keep warm on low heat.

Prepare the grilled cheese: Butter one side of each bread slice. Place a slice of cheese between two slices of bread, buttered side out. Repeat for the remaining sandwiches.

Cook the sandwiches: Heat a large skillet over medium heat. Cook the sandwiches until golden brown and the cheese is melted, about 3-4 minutes per side.

Serve: Ladle the roasted tomato soup into bowls and serve with the grilled cheese sandwiches on the side.

Prep Time: 15 minutes

Cook Time: 45 minutes