Preheat the oven to 350 degrees. Spray a 9-inch loaf pan with nonstick vegetable spray and brush with butter. (The batter has a tendency to stick.)

In mixing bowl of electric mixer cream potato with the butter and sugar until light and fluffy. Add the egg yolks one at a time, beating after each addition.

In a separate bowl sift together the rice flour, rice polish, soy flour, baking powder, baking soda, cream of tartar, salt and pepper, if desired. Add to the potato mixture alternately with the milk, stirring after each addition.

Beat the egg whites until softly stiff. Fold into the batter. Pour onto the pan and bake 1 hour. Turn loaf out on wire rack to cool.

Innovations: Whirl 1 cup sunflower seeds in food processor until coarsely chopped. Add to the batter just before the egg whites are folded in. Do no attempt to use whole seeds in batter as they will all end up in the middle of the loaf.

A second loaf and my favorite: Add 2 teaspoons of cinnamon when sifting the dry ingredients. Add 1 cup of coarsely chopped pecans and 1/2 cup currants, scalded, drained, and dried, before folding in the egg whites.