Preheat the oven to 350F. In a small dish, make the flax egg by combining the flax meal and warm water and set aside.
In a medium mixing bowl, combine the dry ingredients and mix well. Create a well in the center of the dry mix and add the rest of the ingredients (including the flax egg and sugar). Mix the wet ingredients in the center together first, working your way out to incorporate all of the dry. This will be a thick batter.
Add the chopped dark chocolate to the batter and mix to incorporate throughout. Transfer the batter into a parchment lined 8×8 baking dish (or similar) and press evenly into the pan using a spatula or your hands.
Bake in the oven for 20 to 22 minutes (just when the edges begin to brown, but do not overbake) then remove and let it cool on the counter for 15-20 minutes before slicing.
Enjoy!!! Store leftovers in an airtight container at room temperature.
(Adapted from Faring-Well)