Step 1: Prepare the Soup : Heat olive oil in a large pot. Add diced onion and cook until soft and translucent. Stir in garlic and cook for 1 minute. Add crushed tomatoes, broth, sugar, basil, salt, and pepper. Simmer for 15 minutes, stirring occasionally. Blend with an immersion blender until smooth. Stir in cream if using.
Step 2: Prepare the Sandwiches : Use Halloween cookie cutters to cut bread slices into spooky shapes. Butter one side of each slice. Place cheese slices between two bread cutouts (butter side out). Heat a skillet over medium heat and cook sandwiches until golden brown and cheese is melted (about 2–3 minutes per side).
Step 3: Serve : Ladle tomato soup into bowls or small cups. Arrange spooky grilled cheese shapes on the side or float them on top. Garnish soup with a swirl of cream or a sprinkle of fresh herbs if desired.