Preheat oven to 325 degrees.
Spray an 8x8 pan (glass or metal) with cooking spray.
Mix water, oil, and eggs together in a large bowl.
Add brownie mix, oatmeal, brewer's yeast, and flax seed and stir until well mixed. Pour into the pan.
Bake for 37-42 minutes, which will be slightly less than the box will say. You want the edges to be set and the center to lightly spring back to the touch.
Cool for 20-30 minutes.
