In a large saucepan cook the onion in hot butter over medium heat for 5 minutes or until tender. Stir in apples and curry powder. Add chicken broth. Bring mixture to boiling; reduce heat. Simmer, uncovered, about 15 minutes or until apples are very tender. Stir in milk. Cook and stir until heated through. If you like, use a potato masher to slightly mash apples.