Pre-heat oven to 400ºF and line a baking sheet with parchment paper, if desired.
Place cut "chips" on the baking sheet and toss with oil, salt and pepper. Space out "chips" so they do not touch and have space in between to crisp up.
2 large russet potatoes, 2 teaspoons oil, 1 teaspoon fine sea salt, 1/2 teaspoon black pepper
Bake for 20 minutes. After 20 minutes take out of oven and flip chips to crispy on the other side and bake for an additional 20 minutes, or until crispy on the outside and tender on the inside. (See note)
Meanwhile begin to prepare fish: cut into 4 even portions. Depending on the cut of your fish will decide how to portion it. Pat with paper towel to dry it over, and season with 1 teaspoon salt and 1/2 teaspoon pepper.
1-1/2 lbs. white flesh fish, 2 teaspoons fine sea salt, 1/2 teaspoon ground black pepper
Heat oil in a heavy-bottomed tall pot over medium heat. We used a smaller pot that required less oil to submerge the fish. You want the oil to reach about 2-1/2" inside the pot.
Make the batter for the fish by whisking together tapioca, baking soda, 1 teaspoon salt, eggs and white vinegar until fully combined.
3/4 cup tapioca starch, 1/2 teaspoon baking soda, 2 eggs, 1 teaspoon white vinegar
When oil has reached a temperature of 350º to 370º (we use a Thermapen for this!) take a piece of fish and submerge in batter. Working quickly take out of batter before placing inside of oil. Continue with additional fish as space is available. We were able to fry two pieces at once. Flip fish after 2-3 minutes. Monitor the frying temperature to ensure it doesn't dip below 350º for too long and adjust heat as needed. Fry fish until it reaches a temperature of at least 145º and is golden brown on the outside, 5-7 minutes depending on the thickness of your fish.
3 cups avocado oil
Between frying batches of fish make sure oil temperature returns to 350º. Continue to fry until all fish has finished. Place fried fish on paper towel to drain of excess oil. Season with salt, if desired.
Make tartar sauce by combining all ingredients in a small bowl.
1/3 cup avocado oil mayo, 1 tablespoon relish or chopped dill pickle, 1 tablespoon fresh herbs, 2 teaspoons lemon juice, 1/4 teaspoon fine sea salt
Serve fish and chips immediately with tartar sauce.