Prepare the strawberry sauce: In a large saucepan, combine the frozen strawberries, maple syrup, and 2 tablespoons water. Bring the mixture to a boil. Then reduce the heat to medium-low and simmer for 10 to 15 minutes, or until the sauce reaches a syrupy consistency and coats the back of a spoon. As the sauce simmers, break up the whole berries with a wooden spoon or fork.
While the sauce is simmering, prepare the pancake batter: In a large mixing bowl, whisk together the flours, cocoa, sugar, flaxseed, baking powder, and salt.
In a medium bowl, lightly beat the whole egg and egg white. Then add the milk, oil, and vanilla, and whisk until combined.
Pour the wet ingredients over the dry ingredients and stir until the batter is just blended and no dry streaks remain. Take care not to overmix, as this will cause the pancakes to be chewy. Delicately fold in the chocolate chips. If time allows, let the batter rest for 10 minutes.
When the strawberry sauce has reached a syrupy consistency, remove the pan from the heat.
Liberally coat a large skillet or griddle with oil spray. Preheat it over medium heat. When the pan is nice and hot (after about 2 minutes), ladle about ¼ cup batter per pancake onto the surface.
Cook the pancakes until small bubbles form around the edges, 1 to 2 minutes. Flip the pancakes over and cook about 1 minute longer, until the center is cooked. Re-coat the skillet with oil spray between batches to prevent the pancakes from sticking.
To serve, top 2 pancakes with about 1/3 cup warm strawberry sauce and a sprinkling of chocolate chips on each plate.