Potato and Broccoli Soup

2 tablespoons butter 1 onion, chopped 2 cloves garlic, minced 1 3/4 pounds broccoli, thick stems peeled and diced (about 2 cups), tops cut into small florets (about 1 quart) 1 1/2 pounds boiling potatoes (about 5), peeled and cut into 1/2-inch cubes 3 cups canned low-sodium chicken broth or homemade stock 3 cups water 1 3/4 teaspoons salt 1/4 teaspoon fresh-ground black pepper 1/2 cup grated Parmesan cheese

In a large pot, melt the butter over moderately low heat. Add the onion; Cook, stirring occasionally, until translucent, about 5 minutes. Add the garlic, broccoli stems, potatoes, broth, water, salt, and pepper. Bring to a boil. Reduce the heat and simmer until the vegetables are almost tender, about 10 minutes. In a food processor or blender, pulse the soup to a coarse puree. Return the soup to the pot and bring to a simmer. Add the broccoli florets and simmer until they are tender, about 5 minutes. Stir 1/4 cup of the grated Parmesan into the soup, and serve the soup topped with the remaining cheese.   recipe sourc here