Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Cut potatoes into ½-inch-thick wedges. Thinly slice scallions, separating whites from greens; finely chop whites until you have 1 TBSP (2 TBSP for 4 servings). Trim, peel, and grate carrot on the largest holes of a box grater; transfer to a medium bowl. Finely chop chili, removing seeds for less heat.

Toss potatoes on a baking sheet with a drizzle of oil, half the paprika, salt, and pepper. Roast until golden brown and crispy, 20-25 minutes. Meanwhile, in a small bowl, combine mayonnaise, mustard, 1 package sour cream (2 packages for 4 servings), scallion whites, remaining paprika, 1 tsp vinegar (2 tsp for 4), and a pinch of chili to taste. Season with salt and pepper. Set aside.

Meanwhile, to bowl with carrot, add cabbage, 2 TBSP scallion greens (4 TBSP for 4 servings), 2 packages sour cream (4 packages for 4), 1½ tsp sugar (3 tsp for 4), and remaining vinegar. Season with a big pinch of salt and pepper; toss to combine.

Halve tilapia 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.

Heat a ⅓-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 tilapia 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 paper-towellined plate and season with salt. (For 4 servings, fry fish in batches.)

Divide tilapia, slaw, and potatoes between plates. Serve with remoulade on the side. For an extra kick, drizzle tilapia with hot sauce. Garnish with any remaining scallion greens.