Bring all refrigerated ingredients to room temperature. Grease a 5 x 9-inch loaf pan.
In the bowl of a stand mixer, combine eggs, oil, and lemon juice. In a large measuring cup, combine water, 1 tablespoon sugar, and yeast; let stand for 5 minutes, or until foamy. In a medium bowl, combine tapioca starch flour, brown rice flour, dry milk powder, xanthan gum, salt, flax seed, and 3 tablespoons sugar. Add yeast mixture to the egg mixture, then slowly add dry ingredients a little at a time until completely incorporated. Mix batter on high speed for 31/2 minutes, then pour into prepared pan.
Cover bread with foil and place in a cold oven. Set a pan of hot water on a lower shelf underneath the bread. Leave for 10 minutes with oven door closed. (This will cause the tread to rise quickly.) Remove bread from oven (do not uncover) and place in a warm place in the kitchen.
Preheat I oven to 400°F Bread will continue to rise as oven preheats.
Uncover bread and bake for 10 minutes to brown the top. Cover bread with foil and continue to bake bread for 30 minutes. Turn bread out onto a cooling rack. When completely cooled, wrap tightly to maintain freshness for as long as possible.
TIPS: If humidity is high, reduce the amount of water in the recipe to avoid over rising. Many gluten-free bakers experience the frustrating situation in which a beautiful loaf of bread deflates once removed from the oven. You will need to experiment a little to get just the right amount of water in your bread depending on the humidity in the air. If in question, use less water than the recipe calls for.
You may use rapid rise yeast instead of regular yeast. If doing so, eliminate the cold oven rise method with a pan of hot water, follow yeast package directions instead for rise time.
Pour batter into English muffin rings, follow directions above. Bake for just 15 minutes. Once completely cooled these buns freeze well. Always serve buns warmed, otherwise they will be crumbly.