Mix together the minced onion, bread crumbs, egg, egg white, milk, celery, cilantro and 1 cup of the black beans. Use a fork, mashing and blending until smooth.
Fold in the 1/2 cup whole black beans and chill for at least an hour.
Pat together into 8 cakes each one about 3 inches in diameter and one inch thick.
Preheat oven to 350°F.
Arrange the black bean cakes on a non-stick cookie sheet and place in the oven for 10 minutes. Turn the cakes over and switch the oven to broil. Broil for 4 minutes.
