In a large bowl, mix together the flours, brown sugar, baking powder, baking soda and salt. In a medium bowl, whisk together the egg yolks, 1 1/2 tablespoons of the oil, plantain, and buttermilk. Add the liquid mixture to the dry mixture, along with the walnuts, and stir until batter is just mixed. There will be lumps in the batter.
In another bowl, beat the egg whites to soft peaks and fold them into the batter.
Heat a griddle over low heat and brush with some of the remaining 1/2 tablespoon of oil. Drop the batter onto the griddle by tablespoons and cook the pancakes for 1 to 2 minutes, or until bubbles form on top and bottom is golden. Flip pancakes and cook for another minute or until undersides are golden.
Using a spatula, transfer pancakes to a platter and keep warm until all of the pancakes are cooked, repeating the process with the remaining oil for brushing the grill.
Serve pancakes with the Walnut Coconut Yogurt and maple syrup, if desired.
c.1996, M.S. Milliken & S. Feniger, all rights reserved