In a blender, add: egg yolks, salt, buttermilk and oil. Blend. Add rice flour, corn flour, baking soda and sugar. Blend.
In a separate bowl, beat egg whites till stiff, not dry, and add baking powder. Fold mixture from blender into stiffly beaten egg whites.
Gently pour into 12 greased muffin tins. Bake 350 oven for 20-25 minutes. For mini-muffins, bake 13-15 minutes depending on the size of the pans.