Combine the flour, oat bran, cocoa, sugar, milk powder, and baking soda in a large bowl, and stir to mix well.
Stir in the chocolate syrup, egg whites, and vanilla extract,.
Fold in the nuts if desired.
Coat an 8-inch square pan with nonstick cooking spray. Spread the batter evenly in the pan, and bake at 325 degrees fahrenheit for 23 minutes, or just until the edges are firm and the center is almost set.
Cool to room temperature, cut into squares, and serve.