Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.
Place avocado in a food processor or blender; blend until smooth. Whisk avocado and coconut oil together in a bowl until smooth.
Whisk flour, coconut sugar, almond milk, cacao powder, baking soda, and salt into avocado mixture until batter is well combined. Spread batter into the prepared dish.
Bake in the preheated oven until brownies start pulling away from the sides and are set in the middle, about 30 minutes.
