In a food processor or high speed blender, blend black beans until they form into a smooth paste.
Add in cocoa powder, flour, baking soda, and salt. Pulse the food process a couple more times to combine.
Then add in sugar, egg, applesauce and vanilla. Run the food processor until everything is completely mixed together.
Spoon mixture into a mini muffin pan. Filling each ¾ full.
Bake for 15-20 minutes, or until the brownies are set, pull away from the side of the pan, and a toothpick inserted in the center comes out clean.
adapted from Simple and Sweets.