1-First: cut the fish fillets into chunks about 2 inches long and 1 inch wide. This helps them fry evenly and gives you that perfect bite-sized piece. Next, in a medium bowl, whisk together 1 1/2 cups beer or seltzer water, 1 cup flour, 1 tablespoon cornstarch, 1 teaspoon salt, 3/4 teaspoon garlic powder, and 1/4 teaspoon cayenne pepper until the batter is thick but smooth.

2-Then: pour 1 1/4 cups panko breadcrumbs into a separate bowl with a plate ready for the breaded fish. Dip each fish piece into the batter, letting excess drip off, then roll gently in panko to coat evenly without clumping. Heat about 1/2 inch of grapeseed oil in a skillet over medium-high heat, and fry the fish in batches of six until golden brown and crisp, about 2-3 minutes per side.

3-While the fish is frying, mix the sauce ingredients: 1 cup sour cream or a mix of 1/2 cup sour cream and 1/2 cup mayonnaise, 2 tablespoons fresh lime juice, 1 1/2 tablespoons chopped cilantro, 1 teaspoon lime zest, and salt to taste; set it aside. Drain the fried fish on a wire rack to maintain crunch, then warm the 15 corn tortillas in a skillet. Finally, assemble the tacos using two fish pieces each, topped with 2 1/2 cups shredded cabbage, 2 seeded and diced tomatoes, 2 thinly sliced avocados, and a tablespoon of sauce, and serve with fresh lime wedges.