Chicken and Corn Soup

1 small onion, chopped
2 carrots, diced
2 T butter
5 1/4 C chicken broth
4 large potatoes, peeled and diced
3-14 ¾ oz cans cream-style corn
1-9 oz pkg frozen chopped spinach, thawed and squeezed dry
2 C cooked shredded chicken
1/2 tsp black pepper

In a soup pot over medium heat, melt butter; sauté onion and carrots for five to six minutes, or until tender. Add chicken broth and potatoes. Bring to a boil and cook 12 to 15 minutes, or until potatoes are fork tender.  Add remaining ingredients and cook eight to ten minutes, or until heated through. Serve immediately.