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

Peel and dice sweet potatoes into ½-inch pieces; transfer to a medium pot with enough salted water to cover by 2 inches.

Bring to a boil and cook until tender, 15-20 minutes. Reserve ½ cup sweet potato cooking liquid, then drain and return sweet potatoes to pot. Keep covered off heat until ready to mash.

While sweet potatoes cook, trim and finely chop scallion greens (save whites for another use). Quarter pattypan squash lengthwise.

In a small bowl, combine mayonnaise, mustard, half the garlic powder (you’ll use the rest in the next step), and ½ tsp sugar (1 tsp for 4 servings). Season with salt and pepper. Transfer 2 TBSP sauce (4 TBSP for 4) to a separate small bowl; reserve for serving.

Melt 1 TBSP butter (2 TBSP for 4 servings) in a large pan over medium-high heat. Add panko and toast, stirring, until golden and fragrant, 2-3 minutes.

Turn off heat; transfer to a shallow dish and stir in Parmesan, half the scallion greens, remaining garlic powder, and a pinch of salt and pepper. Wipe out pan.

Pat trout* dry with paper towels; season with salt and pepper. Drizzle skin sides with oil; rub to coat.

Place trout, skin sides down, on a baking sheet. (TIP: Line with aluminum foil first for easy cleanup.) Evenly spread tops with 1 tsp sauce each; mound with panko mixture, pressing firmly to adhere.

Roast on top rack until trout is cooked through and cheese melts, 10-12 minutes.

Meanwhile, heat 1½ tablespoons cooking oil (3 TBSP for 4 servings) in a large sauté pan over medium-high heat. Add squash to hot pan. Cook 4-5 minutes, or until squash is lightly browned and tender, stirring occasionally.

Remove from heat; stir in almonds and 1 TBSP butter (2 TBSP for 4 servings). Continue to stir until butter is melted and almonds are golden, 30-60 seconds. (TIP: Return pan to low heat if needed to melt butter.) Cover to keep warm.

While squash cooks, to bowl with reserved sauce, add water 1 tsp at a time until mixture reaches a drizzling consistency.

To pot with sweet potatoes, add sour cream, 1 TBSP butter (2 TBSP for 4 servings), and a big pinch of salt. Mash until smooth, adding splashes of reserved sweet potato cooking liquid as needed.

Stir in remaining scallion greens; taste and season with salt and pepper.

Divide trout, mashed sweet potatoes, and pattypan squash between plates. Top trout with reserved sauce and serve.