Manhattan clam chowder is a clam and tomato-based chowder that has a thin red broth and contains a mix of vegetables and starch. It's seasoned similarly to New England clam chowder, with thyme and parsley. New England clam chowder is a thick clam and milk-based chowder that uses many of the same vegetables and starch as it's Manhattan-style counterpart. They are both hearty and delicious soups!