Adjust rack to upper position and preheat oven to 425 degrees. Wash and dry all produce. Place 3 TBSP butter in a small bowl and bring to room temperature. (TIP: Alternatively, microwave butter in bowl until softened, about 15 seconds.) Cut potatoes into 1/2-inch-thick wedges. Pick 2 TBSP rosemary leaves from stems; mince leaves. (Save remaining rosemary sprigs for later.) Mince or grate garlic.

Toss potatoes on a baking sheet with a drizzle of olive oil, minced rosemary, half the garlic, and a pinch of salt and pepper. Roast until browned and tender, about 30 minutes (we’ll add more to the sheet halfway through). Meanwhile, zest and quarter lemon. Squeeze 2 TBSP lemon juice into another small bowl. Stir lemon zest into bowl with softened butter.

Pat chicken dry with paper towels; season all over with salt and pepper. Heat a large drizzle of olive oil in a large pan over medium-high heat (use a nonstick pan if you have one). Add chicken and cook until browned and cooked through, 5-7 minutes per side. Turn off heat; transfer chicken to a plate. Meanwhile, use a heavy-bottomed pan or mallet to pound peppercorns in their bag until coarsely ground.

Once potatoes have roasted 15 minutes, remove baking sheet from oven and push potatoes to one side. Add green beans and whole rosemary sprigs to empty side. Toss green beans with olive oil, salt, and pepper. Return to oven and roast until veggies are browned and tender, about 15 minutes more.

Add crushed peppercorns and remaining garlic to pan used to cook chicken. Cook on medium-high until lightly browned, about 30 seconds. Add stock concentrates, reserved 2 TBSP lemon juice, and 1/2 cup water. Bring to a simmer, then reduce heat to medium and stir in sour cream. Cook until sauce is creamy, 1-2 minutes more. Stir in lemon butter.

Divide potatoes, green beans, and chicken among plates. Top chicken with pan sauce. Serve with any remaining lemon quarters on the side for squeezing over