In a large saucepan, saute onions in oil until tender. Stir in the roasted peppers, chiles, cumin, salt and coriander. Cook and stir for 2 minutes. Stir in potatoes and broth; bring to a boil.
Reduce heat; cover and simmer for 10-15 minutes or until potatoes are tender. Stir in cilantro and lemon juice. Cool slightly. In a blender, process the cream cheese and half the soup until smooth. Return all to pan and heat through.