Preheat oven to 350°F/175°C. Spray a 9x9 inch square baking pan with a light coating of vegetable spray.
In a mixing bowl, stir together the vegan butter and sugar. Stir in the chia seeds, yogurt, and almond milk.
Add oats to a food processor or blender and pulse until a coarse flour forms. Add the oat flour along with the cocoa powder and baking powder in with the chocolate mixture. Stir until just combined.
Spread the batter into the prepared pan. Bake for 20 to 24 minutes.
Make the ganache by combining chocolate chips and plant-based milk in a microwave-safe bowl. Stir to coat the chocolate chips then cook for one minute in the microwave. Allow it to sit for 1 to 2 minutes, then stir to combine.
Once the brownies are done and have cooled for about 5 minutes, drizzle with chocolate ganache and use a spatula to spread it out evenly across the brownies. Refrigerate for about 30 minutes to allow the chocolate to set.
Notes
Use your favorite plant-based milk for the ganache topping, such as soy milk, almond milk, or even creamier versions, like cashew milk.