Niki Nichols and her husband were trying to work more fish into their diets when they came up with this colorful sandwich. Now it's in their regular weeknight rotation.
Vegetable oil for frying
1/2 cup each cornstarch and flour
1 1/2 teaspoons baking powder
1 1/2 teaspoons kosher salt, divided
3/4 to 1 cup club soda
1 pound cod fillet, cut into 12 equal pieces
4 bolillos (Mexican French-style rolls) or regular French rolls, split lengthwise almost but not quite all the way through
1/2 cup mayonnaise
2 teaspoons Sriracha chili sauce
1 1/2 cups mixed lettuces
2 radishes, thinly sliced
1 medium carrot, coarsely shredded
1 jalapeño chile, very thinly sliced
2 tablespoons each lime juice and vegetable oil
How to Make It
Preheat oven to 350°. Pour oil into a wide, heavy, medium pot to a depth of 2 in. and heat over medium-high heat until temperature reaches 375° on a deep-fry thermometer. Meanwhile, in a medium bowl, mix cornstarch, flour, baking powder, 1/2 tsp. salt, and 3/4 cup club soda until as smooth as pancake batter, adding more club soda if needed.
Working in 3 or 4 batches, drop fish pieces into batter, then carefully lower into oil and fry until golden and crisp, 2 to 3 minutes per batch. Using a slotted spoon, transfer fish to paper towels to drain. Sprinkle with remaining 1 tsp. salt.
Heat rolls in oven until lightly toasted, about 3 minutes. Mix mayonnaise and Sriracha. In a medium bowl, toss lettuces, radishes, carrot, and jalapeño with lime juice and 2 tbsp. oil.
Spread 2 tbsp. mayonnaise mixture on cut sides of rolls. Fill each roll with cod. Top with salad mixture and serve with extra Sriracha if you like.