Combine the flours, starches, sugar, xanthan gum, cinnamon, salt, baking soda, and baking powder in a mixing bowl.
Add the oil, eggs, milk, and vanilla. Stir to mix well.
Stir in the zucchini and nuts.
Spoon into a greased muffin tin and bake at 400 degrees for 18 minutes.
Cool for a few minutes in the pan then transfer to a wire rack.
*Toasting the nuts before adding them to the batter brings out their flavor. It is best to toast them whole and then chop them. I usually forget that, however, and toast them after they are chopped. You just have to watch them very carefully because they will easily burn.
Recipe by The Gluten-Free Homemaker at http://glutenfreehomemaker.com/zucchini-muffins/