- 2 tablespoons olive oil
- 1 medium onion, finely chopped
- 4 garlic cloves, minced
- Coarse salt and ground pepper
- 2 tablespoons tomato paste
- 2 tablespoons balsamic vinegar, plus more for seasoning, if desired
- 2 cans (14 1/2 ounces each) diced tomatoes in juice
- 2 cans (14 1/2 ounces each) cannelini beans or chickpeas, rinsed and drained
- 1 bunch (about 1 pound) broccoli rabe, cut crosswise 1 inch thick and well washed, with water still clinging to it (blanched if desired)
- 4 thick slices rustic whole-wheat bread, toasted
- Heat oil in a large saucepan over medium heat and add onion and garlic. Season with salt and pepper; cook, stirring frequently, until onion is softened, 4 to 5 minutes.
- Add tomato paste and vinegar; cook, stirring frequently, until slightly darkened, 2 to 3 minutes.
- Add tomatoes (with their juice), beans, broccoli rabe, and 4 cups of water. Bring to a boil, reduce heat to medium, and simmer, stirring occasionally, until broccoli rabe is tender, 8 to 10 minutes. Season with balsamic vinegar, salt, and pepper to taste.
- To serve, place a slice of toasted bread in the bottom of each serving bowl; ladle soup over toast.
Add freshly grated Parmesan cheese to give this soup a more robust flavor.