Chipotle peppers add both heat and a distinctive sweet, almost cocoa-like flavor to this creamy chowder. Find canned chipotle peppers in adobo sauce in the supermarket or at a Mexican market. For less heat, substitute chopped green chile peppers.
Heat oil in a large saucepan over medium heat. Add sweet pepper, chopped onion, and cumin; cook for 3 minutes, stirring occasionally.
Carefully add chicken broth, potatoes, the water, and chipotle peppers. Bring to boiling; reduce heat. Simmer, covered, about 8 minutes or until potatoes are tender. Stir in chicken.
Gradually stir about 1/3 cup of the milk into cornstarch in a small bowl; stir into broth mixture in saucepan. Add the remaining milk. Cook and stir over medium heat until thickened and bubbly. Cook and stir for 2 minutes more. Garnish with sliced green onions, if desired. Makes 4 servings.