Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Cut potatoes into 1/2-inch-thick wedges. Trim and thinly slice scallions, separating whites from greens; finely chop whites until you have 1 TBSP (2 TBSP for 4 servings). In a small bowl, combine mayonnaise, mustard, chopped scallion whites, half the sour cream, half the paprika, and 1 tsp vinegar (2 tsp for 4). Season with salt and pepper. Set aside.

Toss potatoes on a baking sheet with a drizzle of oil, remaining paprika, salt, and pepper. Roast on top rack until golden brown and crispy, 20-25 minutes. Meanwhile, in a large bowl, combine coleslaw mix, scallion greens, remaining vinegar, and 11/2 tsp sugar (3 tsp for 4). Season with salt and pepper; toss to combine. Set aside, tossing occasionally, until ready to serve.

Halve rockfish fillets lengthwise (you’ll have a larger piece and a smaller piece). Pat dry with paper towels and season all over with salt and pepper. In a shallow dish, combine Blackening Spice, remaining sour cream, and 1 TBSP water (2 TBSP for 4 servings). On a plate, combine panko and cornstarch; season with salt. Dip each fillet into sour cream mixture, then press into panko mixture, coating all over and pressing to adhere.

Heat a 1/3-inch layer of oil in a large, preferably nonstick, pan over mediumhigh heat. Once oil is hot enough that a pinch of breadcrumbs sizzles when added to the pan, add rockfish and cook until crust is golden and fish is cooked through, 2-3 minutes per side. (TIP: The smaller pieces will cook faster.) Transfer to a papertowel- lined plate and season with salt. (For 4 servings, fry rockfish in batches.)

While fish cooks, halve and toast buns. Place 1 TBSP butter (2 TBSP for 4 servings) in a small microwavesafe bowl; microwave until melted, 30 seconds. Brush cut sides of toasted buns with butter.

Divide buns between plates. Fill with rockfish, coleslaw, and remoulade. If you want an extra kick, drizzle with hot sauce. Serve with potato wedges and any remaining remoulade and coleslaw on the side.