Preheat the oven to 350°F. Lightly oil a 9″ x 9″ baking pan.
Put the black beans, eggs, oil, vinegar, and vanilla in the blender. Mash the beans a little with a spoon or spatula. Then blend until mixture is smooth.
Add the cocoa powder, sugar, baking soda, baking powder, and coffee. Blend just until smooth. DO NOT OVERMIX!
Pour batter into the prepared pan.
Drop the chocolate hazelnut spread by tablespoonful around the batter and swirl with a knife.
Bake for 18 to 20 minutes until brownies are set up and a toothpick tests clean. Allow brownies to cool 15 minutes before cutting into them.