Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.

Cut potatoes into ½-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). Finely chop chili. Trim, peel, and grate carrot on the largest holes of a box grater; place in a medium bowl.

Toss potatoes on a baking sheet with a drizzle of oil, salt, and pepper.

Roast on top rack until golden brown and crispy, 20-25 minutes.

Meanwhile, in a small bowl, combine mayonnaise, mustard, chopped scallion whites, one packet sour cream (two packets for 4 servings), 1 tsp vinegar (2 tsp for 4), and a pinch of chili to taste. (You’ll use the rest of the sour cream and vinegar later.) Season with salt and pepper. Set aside.

To bowl with carrot, add cabbage, two packets sour cream (four packets for 4 servings), remaining vinegar, 2 TBSP scallion greens (4 TBSP for 4), and 1½ tsp sugar (3 tsp for 4). (You’ll use the rest of the sour cream in the next step.)

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.

In a shallow dish, combine Old Bay Seasoning, remaining sour cream, and 1 TBSP water (2 TBSP for 4 servings).

On a plate, combine panko and cornstarch.

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 medium-high heat. Once oil is hot enough that a pinch of panko mixture sizzles when added to pan, add tilapia and cook until crust is golden and fish is cooked through, 2-3 minutes per side (the smaller pieces will cook faster). (For 4 servings, fry fish in batches.)

Transfer to a paper-towel-lined plate.

Divide potatoes, slaw, and tilapia between plates. Serve with spicy remoulade. Garnish with any remaining scallion greens.