Start by cutting the white fish fillets into evenly sized strips, approximately 1-inch wide.

In a large mixing bowl, whisk together all-purpose flour, cornstarch, baking powder, garlic powder, paprika, salt, and pepper until well combined.

One by one, dip each fish strip into the batter, ensuring they're well-coated.

Heat oil over medium-high heat until it reaches 350°F (175°C).

Carefully add the battered fish strips to the hot oil in small batches and fry for 2-4 minutes, turning once.

In a mixing bowl, combine the finely shredded cabbage, sliced red onion, chopped cilantro, and jalapeño if using.

In a separate bowl, mix together sour cream, mayonnaise, lime juice, and minced garlic until smooth.

Warm the corn tortillas in a skillet over medium heat for about 30 seconds on each side.

In each warm tortilla, layer a generous spoonful of slaw, followed by the crispy fish, and drizzle with the creamy sauce.

Serve with lime wedges on the side.