In a large mixing bowl combine flours, baking powder and xanthan gum; cut in butter with pastry blender.
In another bowl mix together the honey, eggs, grated lemon peel, lemon juice and water. Add liquid mixture to the dry ingredients and stir with fork.
Turn dough out onto a lightly floured surface and knead 10 times. Pat dough into round shape 1" thick and brush with lemon juice; sprinkle with 1 tablespoon of granulated sugar. Cut into wedges and place edges onto baking sheet and bake for 30 minutes.