Preheat oven to 375 degrees.
Grease three 5½"x 3"x 2" mini-bread pans (or one 9"x 5" loaf pan)
1 cup brown rice flour
1 1/4 cups gluten free oat flour
1/4 cup tapioca flour
1/4 cup arrowroot flour
1/4 cup millet flour
1 1/2 teaspoons salt
1 tablespoon baking powder
1 1/4 teaspoons xanthan gum
2 large eggs
3 tablespoons pure maple syrup
1 bottle gluten-free beer (12 oz.) I used New Planet Gluten Free Beer, it has a little bit of orange so it adds a depth of flavor.
In a medium size bowl, whisk the dry ingredients together until thoroughly mixed. Make Ahead Note: You can do this days before. Pour the mixed dry ingredients into a freezer bag or a tightly covered container until you are ready to make bread.
In a LARGE mixing bowl, beat the eggs and maple syrup together until frothy with a whisk. Slowly add the beer, whisking gently; it will be nice and foamy. Immediately, add the dry ingredients; whisk just until smooth and combined. Spoon the batter into the greased mini-pans and smooth out the batter evenly in the pans. (Or you can use one 9x5 inch baking pan)
Place the mini-pans on a baking sheet so they don't get knocked over in the oven; plus they are easier to remove after they are baked. Bake 35-43 minutes or until golden brown and done. Let cool 5 minutes. Gently run a knife around the edges to loosen; turn upside down and give the pans a little pat. Turn the bread right side up and let cool on a wire rack.