Preheat the oven to 180°C (356°F).
Soak and cook chickpeas in water, then blend them until smooth in a mixer.
In a bowl, mix chickpeas, dark chocolate, cocoa powder, sugar, almond flour, baking powder, salt, and milk together.
Pour the batter into a brownie pan.
Bake in the oven at 180°C (356°F) for 20~25 minutes.
Let it cool, then cut into desired servings.