Method:
Preheat oven to 350°F.
Spray an 8-inch square baking pan with natural canola oil spray and set aside.
In a medium mixing bowl, whisk together the cocoa powder, cane sugar, unbleached flour, whole wheat pastry flour, baking soda, and sea salt. Set aside.
In a small saucepan, melt the butter. Remove from heat. Add the cold milk. Gently whisk in the egg and the vanilla. Add this mixture to the dry ingredients and whisk to blend to a completely smooth batter.
Spoon the batter evenly into the prepared pan. Bake for 30 minutes. Cool in the pan. Cut into 16 squares.