Preheat oven to 400 degrees. Line muffin tin with baking cups. This recipe makes 6 regular size muffins.
In a large bowl, combine flours, arrowroot, baking powder, xanthum gum, cinnamon, salt and sugar. Mix together well. Set aside.
Crack egg into a small bowl and whisk until frothy. Add olive oil, milk and honey. Whisk well. Pour wet ingredients into dry and fold together with a spatula, 15-20 strokes. Add in about ⅔ of the chopped nuts and fold together.
Scoop into prepared muffin cups. Top with remaining nuts and coarse sugar for decoration (optional). Bake in preheated oven for 2 minutes, then reduce temperature to 375 and bake an additional 25 minutes, or until tops spring back when gently poked.