1 box BC Fudge Brownie Mix
Follow directions and add 2 T flaxseed meal with the water.
You may want to let the meal and water sit a bit to get gooey. This apparently is a common egg substitute used in baking. But in the recipe you are kind of adding an "extra" egg with this to make the brownies cakier. Also it boosts the fiber content.
Bake as directed in a 13x9 pan and slice up with a plastic knife after cooling a bit.