Preheat oven to 450ºF. Butter or spray with cooking oil a 10-inch pie plate and one ramekin.
Mix together all liquid ingredients in one bowl and whisk together the dry ingredients in another. Slowly pour the dry ingredients into the liquid bowl while stirring. Beat until totally combined.
Pour gluten free batter into prepared pie plate, leaving at least ¼ inch between the batter and the rim of the pie plate. Pour any remaining batter into prepared ramekin(s). Smooth the top of the pie with a rubber spatula.
Place gluten free pie in preheated over and bake for 15 minutes. Then reduce heat to 375ºF and bake for 30 more minutes or until a knife inserted into the pie comes out clean.
TIP: If using a commercial all-purpose gluten free flour blend that does not contain xanthan gum, add ½ teaspoon xanthan gum to the dry ingredients. Results may vary, depending on the gluten free flour blend.