Preheat the oven to 350°F. Line an 8-inch square pan with aluminum foil and mist lightly with cooking spray.
In a large bowl, whisk the avocado and coconut oil together until smooth. Whisk in the flour, cocoa powder, sugar, baking soda, salt, and coconut milk until well combined.
Spread the batter evenly into the bottom of the prepared pan and bake for 15-20 minutes, until a toothpick inserted into the center comes out clean.
Cool brownies completely in the pan on a wire rack. Cut into squares and serve. The brownies will stay fresh for up to 3 days stored in an airtight container at room temperature.
Notes
If you want less of a cake-like brownie, try underbaking them slightly. This will make the brownies fudgy in texture.