Because the best part of tomato soup is dunking a buttery grilled cheese into the bowl.
- Make soup. Melt 1 tablespoon of butter in a large pot over medium heat. Add onion cook until beginning to soften, 2 to 3 minutes. Add tomatoes, stock, 1 teaspoon salt, and 1/2 teaspoon black pepper. Bring to a boil and simmer 15 minutes. Stir in cream, then ladle into bowls. Garnish with fresh basil.
- While the soup is simmering, make the grilled cheese roll-ups. Using a rolling pin, roll bread into flat, 1/4-inch thick squares. Place a cheese slice on each slice of bread and roll up tightly.
- Melt 1 tablespoon of butter in a large nonstick skillet over medium heat. Working in batches, add the roll ups to the skillet, seam side-down. Cook, turning often, until all sides are golden and the cheese has melted, about 3 minutes. Wipe the skillet clean with a paper towel and add more butter before adding more roll-ups.
- Ladle soup into bowls and serve with grilled cheese roll-ups.