Step 1: Make the Soup : Heat olive oil in a large pot over medium heat. Add chopped onion and sauté for 3–4 minutes until soft and translucent. Add minced garlic and cook for 30 seconds until fragrant. Add canned tomatoes (with juice), broth, sugar, salt, and black pepper. Bring to a simmer and cook for 15 minutes to allow flavors to meld. Remove from heat and stir in chopped basil and heavy cream.

Step 2: Blend the Soup : Use an immersion blender to puree the soup until smooth. Alternatively, transfer in batches to a blender and blend carefully. Taste and adjust seasoning with additional salt, pepper, or sugar if needed.

Step 3: Make Grilled Cheese Croutons : Butter one side of each slice of bread.

Place cheese slices between two slices of bread, buttered sides out. Heat a skillet over medium heat and cook sandwiches 2–3 minutes per side until golden and cheese is melted. Cut sandwiches into bite-sized cubes for croutons.

Step 4: Serve : Ladle soup into bowls. Top with grilled cheese croutons. Garnish with extra basil or a drizzle of cream.