Combine flours, baking powder, cinnamon, baking soda and salt. Make a well in the center.
Beat eggs. Stir in brown sugar, applesauce and canola oil.
Pour egg mixture into the well in flour mixture. Stir until batter is combined but still slightly lumpy. Fold in rhubarb.
Grease a standard-size (4-ounce) muffin tin or line with paper liners. Spoon about 2 tablespoons batter into each cup. Sprinkle a pinch of cinnamon and brown sugar over the batter in each cup, if using.
Bake 15 minutes, or until muffins spring back when touched.
Recipe by Amish 365 at https://www.amish365.com/sunday-night-recipe-rhubarb-applesauce-muffins/