Black Bean and Sweet Potato Stew

2 cups finely chopped onions

2 T. minced fresh ginger

2 t. Ancho chili powder

1 t. New Mexico chili powder*

1 1/2 t. ground cumin*

1 1/2 pound yams (about 2 medium) peeled, cut into 1/2 inch pieces

2 cups orange juice

2 T. minced garlic

2 15 ounce cans low sodium black beans, rinsed, drained

2 poblano chilies, seeded, chopped

1 red bell pepper, chopped

1 jalapeño, seeded and chopped

Sour cream (fat free) optional

Avocado slices

Orange wedges (optional, however attractive)