Mix together mayonnaise, hot sauce, lemon juice and onion powder, cover and place in the fridge to allow flavors to combine.

Cut cod fillets into four sandwich sized pieces and place in a bowl and set aside.

Mix together 1/4 cup of flour, 1/2 tsp salt and the black pepper and tip onto a plate and set aside.

In a mixing bowl, combine 1 cup of flour, baking powder, garlic and onion powder, the remainder of the salt and set aside.

Whisk together water, egg and 2 tbsp lemon juice then add to flour mixture in mixing bowl.

Whisk ingredients into a batter, whisk vigorously until batter foams.

Drizzle 2 tbsp of lemon juice over cod pieces then coat cod on all sides in set aside flour mixture on plate and shake off excess.

Pour cooking oil into a skillet until it is filled half way, then place on high heat.

Dip cod pieces into batter and when oil is hot but not smoking, carefully place cod into the oil.

Repeat until all cod pieces are drenched in batter and placed in the skillet.

Watch the temperature of the oil, if it appears to be browning the cod pieces too quickly lower the heat to medium and raise if needed to keep temperature as constant as you can.

Flip cod pieces to achieve an even golden color on both sides, then remove from oil and place on paper towels to absorb excess oil.

Heat brioche buns in a clean skillet (no oil needed) or in the oven.

Smear a generous dollop of the Spicy Aioli on the base of the brioche buns.

Top aioli with lettuce then carefully place a piece of cod on top. Layer a thick slice of tomato, add a less generous dollop of aioli on the tomato, then carefully press the top of the bun to crown your fish sandwich.