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

Peel and dice potatoes into ½-inch pieces. Core, deseed, and dice bell peppers into 1-inch pieces. Halve, peel, and slice onion into ½-inch-thick wedges.

In a small bowl, combine romesco and mayonnaise.

Place potatoes in a medium pot with enough salted water to cover by 2 inches. Bring to a boil and cook until easily pierced by a fork, 15-20 minutes.

Reserve ½ cup potato cooking liquid (1 cup for 4 servings), then drain and return potatoes to pot.

While potatoes cook, toss bell peppers and onion on a baking sheet with a large drizzle of oil, half the Savory Paprika Blend (you’ll use the rest in the next step), salt, and pepper.

Roast until browned and tender, 15-18 minutes.

Meanwhile, halve tilapia* lengthwise (for each fillet, you’ll have a larger piece and a smaller piece). Pat dry with paper towels.

In a shallow dish, combine sour cream, remaining Savory Paprika Blend, 1 TBSP plain water (2 TBSP for 4 servings), salt, and pepper.

On a plate, combine panko and cornstarch.

Dip each piece of fish into sour cream mixture, then press into panko mixture, turning to coat 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 coated tilapia; cook until crust is golden and fish is cooked through, 2-3 minutes per side. (For 4 servings, work in batches.) TIP: The smaller pieces will cook faster!

Transfer to a paper-towel-lined plate.

While fish cooks, heat pot with potatoes over low heat. Add chimichurri and 1 TBSP butter (2 TBSP for 4 servings).

Using a potato masher or fork, mash potatoes, adding splashes of reserved potato cooking liquid as needed, until smooth and creamy. Season with salt and pepper.

Divide mashed potatoes, roasted veggies, and tilapia between plates. Drizzle fish with romesco aioli and serve.