Weigh or lightly spoon flours into dry measuring cups; level with a knife. Combine flours, cinnamon, and next 6 ingredients (through nutmeg) in a large bowl; stir with a whisk. Make a well in center of mixture. Combine sugar and next 4 ingredients (through eggs); stir with a whisk. Add to flour mixture, stirring just until moist.
Pour batter into an 8 x 4-inch loaf pan coated with cooking spray; smooth top with a spatula. Bake at 350° for 1 hour and 5 minutes or until very firm to the touch. Cool 15 minutes in pan on a wire rack; remove from pan. Cool completely on wire rack.
Gluten-Free Baking; The Food Lover's Gluten-Free Cookbook