Preheat oven to 350 degrees F. Line an 8-inch square metal pan with parchment paper or foil. If using foil, grease bottom only.
Process beans, sugar, cocoa powder, baking powder, salt and espresso powder until mixture comes together as a rough paste. Add the vanilla, eggs, oil and syrup. Process until smooth. Stir in ⅓ cup of chocolate chips.
Pour batter into the pan and sprinkle more mini chips over the top.
Bake for about 30 to 32 minutes or until the brownies are set. Let cool in the pan completely before cutting into squares. (They will be soft until refrigerated.)
Notes
When drained and rinsed, the beans should weigh 8 ½ oz. The black beans themselves add a lot of salty flavor, so the recipe only calls for ⅛ teaspoon salt. If you are using unsalted black beans, you may want to add a pinch more salt.