Pat the redfish fillets dry with paper towels. Trim any thin edges so the fillets cook evenly. Season both sides lightly with 1 tsp kosher salt and 1 tsp black pepper.

Make the blackening spice

In a small bowl combine 2 tbs paprika, 1 tsp onion powder, 1 tsp garlic powder, 1 tsp dried thyme, 1 tsp cayenne pepper, and 1/2 tsp ground cumin. Stir to blend evenly. Rub about half of the spice mix onto both sides of the fillets, pressing to adhere; reserve remaining spice for extra seasoning or another use.

Heat the pan

Place a heavy skillet (cast iron recommended) over medium-high heat. Add 2 tbs olive oil and 1 tbs unsalted butter. Allow the butter to melt and the oil to shimmer but not smoke — about 1 to 2 minutes.

Blacken the fish

Add the fillets to the hot skillet, pressing down slightly so full contact is made. Cook 3 to 4 minutes on the first side without moving until a dark crust forms. Flip carefully and cook another 2 to 4 minutes until the fish flakes easily with a fork and reaches an internal temperature of 135–145°F (57–63°C) depending on preferred doneness. Remove to a plate and tent loosely with foil to keep warm.

Citrus Slaw

Combine vegetables

In a large bowl toss together 2 cups shredded green cabbage, 1 cup shredded red cabbage, 1 grated julienned carrot, and 1/4 cup chopped cilantro.

Make dressing

In a separate small bowl whisk 2 tbs lime juice, 1 tbs orange juice, 3 tbs mayonnaise, 2 tbs Greek yogurt, 1 tsp honey, 1/2 tsp salt and 1/4 tsp black pepper until smooth.

Dress the slaw

Pour the dressing over the cabbage mixture and toss until evenly coated. Taste and adjust seasoning with extra lime or salt if desired. Let sit for 10 minutes to meld flavors.

Sauce & Assembly

Make the chipotle crema

Stir together 1/2 cup crème fraîche (or sour cream) with 1 tsp minced chipotle in adobo (or 1 tsp chipotle powder) and a squeeze of lime. Thin with 1 tsp water if needed to reach a drizzling consistency. Taste and adjust heat or lime.

Warm tortillas

Heat a dry skillet over medium heat or directly warm tortillas over a low gas flame, about 20–30 seconds per side, until pliable and slightly charred in spots. Keep wrapped in a clean towel to stay warm.

Assemble tacos

Flake the blackened redfish into 8 roughly equal portions. Place a portion in the center of each warm tortilla. Top with a generous spoonful of citrus slaw, a drizzle of chipotle crema, a couple of avocado slices, and a few pickled red onions if using. Serve immediately with lime wedges.