1/2 teaspoon each of garlic powder, black pepper, and onion powder (optional)
1/4 teaspoon salt (optional)
1/2 cup cracker crumbs
In a large bowl, mash the drained black beans. Add the sautéed onions, crumbled bread, and spices. Mix thoroughly. Add about 1/4 cup of cracker crumbs (or just enough to be able to form patties from the mixture). Using your hands, form the mixture into 1/2-inch thick patties. For a breaded burger, gently coat each patty with more cracker crumbs.
In a lightly oiled non-stick pan, fry both sides of the patties. Serve with a garnish of lettuce, tomatoes, avocado, and any other condiments on buns or over a bed or rice.