Combine brown rice flour, cornstarch, baking powder, baking soda, salt and pepper in a large bowl. Whisk to combine.
Whisk in club soda stirring until no lumps remain.
Cover bowl with plastic wrap and let sit at room temperature for 30 minutes.
TARTER SAUCE
Mix all ingredients together in a bowl. Set aside.
FISH
Put cornstarch in shallow bowl.
Pat fish dry with paper towel. Season with salt and pepper.
Dredge in cornstarch shaking off excess. Set onto clean plate.
Pour oil in wok and heat to 375°F.
Prepare paper towel lined plate to set fish on when removed from oil.
Prepare a baking sheet with metal rack and preheat oven to 200°F to keep fish warm before serving.
Dip fish into batter letting excess drip back into the bowl. Place into hot oil and fry for 1 minute. Work with 3-4 pieces at a time allowing the oil to come back to 375°F between batches. Repeat until all fish is cooked once.
Repeat the whole process. Dip the fish into the batter again, cooking until golden brown, about 2 minutes. Set onto paper towel lined plate.
Transfer fish to prepared baking sheet and place in oven to keep warm.
FRENCH FRIES
Add potatoes to oil in batches. Cook 3-4 minutes for thin fries, 5-6 minutes for larger homestyle fries.
Remove with strainer onto a paper towel lined tray.
Notes
*can substitute half brown rice flour and half corn flour