Adjust racks to top and middle positions and preheat oven to 450 degrees. Wash and dry produce.

Dice potatoes into ½-inch pieces. Cut broccoli into bite-size pieces if necessary. Pick and finely chop fronds from dill. 

Toss potatoes on a baking sheet with a drizzle of oil and a pinch of salt and pepper.

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

Meanwhile, 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 and cook until browned and cooked through, 3-5 minutes per side.

Turn off heat; transfer chicken to a cutting board to rest.

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 to rest.

While chicken cooks, toss broccoli on a second baking sheet with a drizzle of oil and a pinch of salt and pepper.

Roast on middle rack until tender, 12-15 minutes.

Heat pan used for chicken over medium heat. Stir in stock concentrate, 2 TBSP water (4 TBSP for 4 servings), and as much chopped dill and mustard as you like.

Remove pan from heat; stir in sour cream and 1 TBSP butter (2 TBSP for 4), scraping up any browned bits from bottom of pan. Season with salt and pepper. TIP: If sauce seems too thick, add more water 1 tsp at a time until it reaches a drizzling consistency.

Use pan used for salmon here.

Slice chicken crosswise.

Divide chicken, potatoes, and broccoli between plates and drizzle with sauce. Garnish with any remaining chopped dill if desired and serve.

Serve salmon as instructed (no need to slice!).