I found an intriguing recipe today - Brownies made with black bean. I would like to try this recipe at some point. If anyone tries this recipe, please post feedback here.
Sans butter:
http://ecochildsplay.com/2009/01/27/black-bean-brownies-recipe/
With butter:
http://www.101cookbooks.com/archives/amazing-black-bean-brownies-recipe.html