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

Trim, peel, and cut carrots on a diagonal into ½-inch-thick pieces. Trim and quarter Brussels sprouts lengthwise (halve any smaller sprouts). Halve, peel, and cut onion into ½-inch-thick wedges.

Toss carrots, Brussels sprouts, and onion on a baking sheet with a large drizzle of oil and chili flakes to taste; season with salt. Roast on top rack until carrots are tender and Brussels sprouts are lightly charred, 18-20 minutes.

Meanwhile, trim and thinly slice scallions, separating whites from greens. Peel and mince or grate garlic.

Pat chicken* dry with paper towels and season all over with salt and pepper.

Heat a drizzle of oil in a large pan over medium-high heat. Add chicken; cook until browned and cooked through, 3-5 minutes per side. Transfer to a cutting board; reserve pan.

Swap in salmon* for chicken. Cook (skin sides down) until skin is crisp, 5-7 minutes. Flip and cook until cooked through, 1-2 minutes more. Transfer to a plate.

Heat 2 TBSP butter (4 TBSP for 4 servings) in pan used for chicken over medium heat. Add scallion whites and garlic; cook, stirring, until fragrant, 30 seconds.

Stir in honey, miso sauce concentrate, and ¼ cup water (½ cup for 4). Bring to a simmer and cook, stirring occasionally, until glaze has thickened slightly, 2-3 minutes more. (TIP: If glaze does not come together, stir in a splash of water.) Taste and season with salt and pepper if desired.

Once veggies are done roasting, sprinkle with sesame seeds; toss to coat.

Thinly slice chicken crosswise.

Divide chicken and veggies between plates. Drizzle chicken with glaze and sprinkle everything with scallion greens. Serve.

Divide salmon (no need to slice!) between