Pat the fish fillets dry with paper towels. In a small bowl combine 2 tbsp olive oil, 2 tbsp lime juice, chili powder, ground cumin, smoked paprika, garlic powder, 1 tsp kosher salt and 1/2 tsp black pepper. Brush or rub the mixture evenly over both sides of the fillets. Let marinate 10–15 minutes at room temperature (or up to 30 minutes in the refrigerator).

Cook the fish

Heat a large nonstick or cast-iron skillet over medium-high heat and add 1 tbsp butter or oil. When shimmering, add the fillets and cook undisturbed 3–4 minutes per side depending on thickness (fish should flake easily and reach 145°F/63°C). For a more charred exterior, finish under high heat for 30–60 seconds. Transfer cooked fish to a plate and let rest 2–3 minutes, then flake into large chunks with a fork.

Slaw

Make the slaw

In a large bowl combine green cabbage, red cabbage, shredded carrot and chopped cilantro. In a separate small bowl whisk together 2 tbsp lime juice, 3 tbsp mayonnaise, 2 tbsp sour cream or Greek yogurt, 1 tsp honey, 1/2 tsp salt and 1/4 tsp black pepper until smooth. Pour dressing over cabbage mixture and toss to coat. Taste and adjust seasoning or acidity. Let sit 10 minutes to soften slightly (or refrigerate up to 1 hour).

Sauce

Prepare the sauce

In a small bowl combine 1/2 cup Greek yogurt, 2 tbsp mayonnaise, 1 tbsp lime juice, 1 tsp minced chipotle in adobo (or 1/2–1 tsp chipotle powder), 1/2 tsp honey and 1/4 tsp salt. Whisk until smooth. If the sauce is too thick, add up to 1 tsp water to reach a drizzleable consistency. Adjust heat and salt to taste.

Tortillas & Assembly

Warm tortillas

Warm tortillas just before serving. Heat a dry skillet over medium-high heat and warm each tortilla 20–30 seconds per side until pliable and slightly charred in spots; alternatively wrap stack in foil and heat in a 350°F (175°C) oven for 8–10 minutes or microwave damp paper-towel-wrapped tortillas for 20–30 seconds.

Assemble tacos

To assemble, place warmed tortilla on a plate. Spoon 2–3 tbsp slaw onto the center, add a few large flakes of cooked fish (about 2–3 oz fish per taco), drizzle 1–2 tsp of the chipotle-lime sauce, top with a couple slices of avocado, a sprinkle of fresh cilantro leaves and optional pickled red onions. Serve with lime wedges on the side for squeezing.

Serve

Serve immediately while fish is warm and tortillas are pliable. Offer extra sauce, hot sauce, and lime wedges at the table.