Preheat your oven to 200°C (400°F). Chop the onion and red bell pepper, then mix them with cherry tomatoes and whole garlic cloves in a baking dish. Drizzle with olive oil and season liberally with salt and pepper. Roast for 40-45 minutes, until the vegetables are soft and caramelized.

Once roasted, transfer the vegetables to a blender along with the roasted garlic, squeezing it out of its skin. Add the cream and fresh basil, then blend until completely smooth and creamy.

Pour the blended soup into a medium pot over low to medium heat. Gently heat the soup for about 5 minutes, stirring occasionally, just until it's warmed through.

While the soup is heating, take slices of your chosen bread and butter one side of each slice generously. Place a slice of cheddar cheese between two buttered bread slices. Preheat a skillet over medium heat, then grill the sandwich for 3-4 minutes on each side until golden brown and the cheese is melted.

Ladle the warm soup into bowls and garnish with fresh basil if desired. Cut the grilled cheese sandwiches into triangles and serve alongside the soup.