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

Cut potatoes into ½-inch-thick wedges. Zest and halve lemon (for 4 servings, zest one lemon and halve both). Trim and thinly slice scallions, separating whites from greens.

Toss potatoes on a baking sheet with a large drizzle of olive oil, half the paprika, half the garlic powder (you’ll use the rest of each spice later), salt, and pepper.

Roast on top rack until browned and tender, 20-25 minutes.

Meanwhile, in a medium bowl, combine mayonnaise, sour cream, juice from half the lemon (whole lemon for 4 servings), half the celery salt (you’ll use the rest later), and 1½ tsp sugar (3 tsp for 4). Add cabbage and scallion greens; toss to coat. Season generously with salt and pepper. Set aside.

Place 1 TBSP butter (2 TBSP for 4 servings) in a small microwave-safe bowl; microwave until melted, 30 seconds.

Slice baguettes lengthwise, stopping before you get all the way through. Brush melted butter onto cut sides of bread. Place, cut sides up, directly on oven rack (or use a baking sheet); toast until golden brown, 2-3 minutes.

While baguettes toast, rinse shrimp* under cold water, then pat dry with paper towels. Toss in a second medium bowl with a large drizzle of olive oil, remaining paprika, remaining garlic powder, remaining celery salt, and a big pinch of salt and pepper.

Heat a large drizzle of olive oil in a large pan over medium-high heat. Once pan is hot, add shrimp and scallion whites. Cook, stirring occasionally, until shrimp are opaque and cooked through, 3-4 minutes.

Turn off heat; stir in 1 TBSP butter (2 TBSP for 4 servings) and lemon zest to taste.

Fill toasted baguettes with shrimp, as much slaw as you like, and hot sauce if desired.

Divide shrimp rolls and potato wedges between plates. Slice remaining lemon into wedges and serve on the side. TIP: If you have ketchup on hand, serve some on the side for dipping.