Ham and Squash Soup

4 tablespoons butter or oil
¼ pound baked ham, chopped
2 carrots, chopped
2 leeks, cleaned and sliced
4 cups water or chicken stock
1 ½ pounds buttercup squash, peeled, seeded, chopped
1 teaspoon dried thyme
1 bay leaf
1 tablespoon tomato paste
1/8 teaspoon ground allspice
Salt and pepper
2 cups half-and-half

Sauté ham, carrots, and leeks on medium until tender.  Add water and bring to boil.  Add squash, thyme, bay leaf, and tomato paste.  Reduce heat, cover and simmer until squash is tender.  Puree and then add allspice, salt, pepper, and half-and-half.  Serve hot.