In a large mixing bowl or the bowl of your stand mixer, mix together the white rice flour, potato starch, tapioca starch, sugar, yeast, salt and xanthan gum.

Slowly pour in the warm milk while mixing on low. Add the butter and beat until thoroughly blended.

Add the eggs one at a time, beating after each addition. Scrape the bottom and sides of bowl. Beat the batter for 3 minutes on high.

Cover bowl and let batter rise for one hour in a warm place.

Scrape down sides of bowl once again to gently deflate the batter. Grease an 8" x 4" loaf pan and pour batter into pan. Smooth out the top using a spatula. Cover (with plastic wrap sprayed with cooking spray) and let rise in a warm place just until loaf barely crowns above the rim of the pan, about 20 to 25 minutes.

Preheat oven to 350 degrees F. Bake the bread until golden brown, about 38 to 40 minutes.