Step 1

Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Dice sweet potatoes into ½-inch pieces. Core, deseed, and dice poblano into ½-inch pieces. Halve, peel, and cut onion into ½-inch-thick wedges; mince one wedge until you have 1 tsp (2 tsp for 4 servings).

Step 2

Toss sweet potatoes, poblano, and onion wedges on a baking sheet with a large drizzle of olive oil, half the cumin, salt, and pepper. (For 4 servings, divide veggies between 2 baking sheets; roast on top and middle racks.) Roast on top rack until lightly browned and tender, 20-25 minutes.

Step 3

Meanwhile, finely dice tomato. Zest and quarter lime (quarter both limes for 4 servings). Mince cilantro leaves and stems. Mince or grate 1 clove garlic (2 cloves for 4). Thinly slice jalapeño into rounds, removing ribs and seeds for less heat; mince a few slices until you have ½ tsp (1 tsp for 4).

Step 4

In a small bowl, combine sour cream, cilantro, minced onion, juice from half the lime, a pinch of minced garlic, a pinch of minced jalapeño, a small pinch of cumin (you’ll use the rest later), and 1 TBSP olive oil (2 TBSP for 4 servings). Taste and add more garlic if desired. Add water 1 tsp at a time until mixture reaches a drizzling consistency. Season with salt and pepper.

Step 5

Pat barramundi dry with paper towels and season all over with salt and pepper. Season flesh sides with remaining cumin; rub to evenly coat. Heat a large drizzle of oil in a large, preferably nonstick, pan over mediumhigh heat. Add barramundi skin sides down. Cook until skin is slightly crisp, 4-5 minutes. Flip and cook until barramundi is opaque and cooked through, 2-3 minutes more.

Step 6

Toss roasted veggies with tomato and lime zest; divide between bowls or plates. Place barramundi on top. Drizzle with creamy salsa verde and scatter with sliced jalapeño if desired. Serve with any remaining lime wedges on the side.