If you really love beans, all you want in a bean soup is beans. There is very little liquid in this soup, but you can certainly add more broth or water if you prefer it soupier. At the other extreme, you can can add less and make it thick enough to serve as a side dish to accompany a nice roast.
2 cups cooked cannellini beans, drained and rinsed if canned
Salt and freshly ground pepper
1 cup homemade beef broth or 1/3 cup canned beef stock diluted with 2/3 cup water
2 tablespoons chopped fresh flat-leaf parsley
Toasted thick slices of crusty bread
Put the oil and garlic in a saucepan. Cook over moderate heat, stirring, until the garlic is a pale gold. Add the beans and a pinch of salt and pepper. Cover and cook gently for 5 minutes.
Transfer 1/2 cup of the beans to a food mill, add the broth and puree back into the pan. Simmer the soup for 5 minutes, then season with salt and pepper. swirl in the parsley. Ladle the soup over the toasted bread and serve.