Preheat the oven to 350 °F. Lightly spray an 8x8-inch baking dish with nonstick spray.
In a large bowl, whisk together the spelt and buckwheat flour, oat bran, flax meal, baking soda, baking powder, cinnamon, ginger, nutmeg and salt.
In a second bowl, whisk together the applesauce, egg whites, and sugar.
Whisk the milk and vanilla extract into the applesauce mixture.
Stir in the melted butter (I like to zap butter for 30 seconds in the microwave to melt it)
Pour the flour mixture into the wet ingredients, and stir the wet and dry ingredients together. Pour the batter into the prepared baking dish and sprinkle course sugar on top for decoration.
Bake for about 30 minutes, until a knife or skewer inserted into the center of the cake comes out clean.