Preheat oven to 350*. Spray a 9x9 baking pan with non stick spray. And 8x8 will work too, but the bake time might be a bit longer.
In a small bowl, combine ground flax, water, and vanilla and set aside.
In a large bowl, combine melted non dairy butter with the cocoa powder using a whisk.
Next add, sugar, and whisk to combine.
Next, add the flax mixture and whisk to combine.
Into the wet ingredients, add flour, baking powder and salt. Using a rubber spatula, stir until everything is just combined.
Add ½ cup chopped chocolate into the batter and stir until evenly distributed.
Scrape batter into prepared pan, pressing it evenly into the corners. Top the batter with the remaining ½ cup of chopped chocolate, gently pressing them into the the batter.
Bake at 350 for 30-35 minutes, turning half way through. A toothpick or a spall paring knife inserted into the center of the brownies will come out with a few moist crumbs attached. Let cool completely, slice into 16 squares, and serve.