Hearty Peasant Soup

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) cannellini 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
Directions
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.
Cook's Note
Add freshly grated Parmesan cheese to give this soup a more robust flavor.