Preheat oven to 350°F. Grease an 8x8-inch baking pan, line with parchment paper.
Measure water in a measuring cup and add flaxseed, stir. Set aside.
Add unsweetened chocolate onto a large heatproof bowl. Melt chocolate over a double boiler. Once chocolate is melted and smooth, remove from the heat. Add to the melted chocolate the flaxseed mixture, oil, sugar, vanilla, and stir until combined. Add flour, baking powder, salt, and chocolate chips. Stir until combined
Scrape batter into prepared pan. Bake for 30-35 minutes. Remove from the oven and set on top a wire rack. Let the brownies completely cool in the pan. Using the parchment paper, lift the brownies from the pan and cut into 16 squares.