Bring a large pot of salted water to a boil. Wash and dry produce.

Trim green beans if necessary. Zest and halve lemon lengthwise; thinly slice half the lemon into half-moons (remove seeds from half-moons). Peel and mince or grate garlic. Roughly chop parsley. Grate Parmesan into a medium bowl.

Once water is boiling, add linguine to pot. Cook, stirring occasionally, until al dente, 9-11 minutes. Reserve 1 cup pasta cooking water (1½ cups for 4 servings), then drain.

While pasta cooks, heat a drizzle of oil in a large pan over medium-high heat. Add green beans, salt, and pepper. Cook, stirring occasionally, until lightly browned and softened, 4-6 minutes.

Turn off heat; transfer green beans to a plate. Toss with a pinch of lemon zest; tent with foil to keep warm. Wipe out pan.

Pat chicken* dry with paper towels. Place between two large pieces of plastic wrap; pound with a mallet or rolling pin until about ½ inch thick. Season all over with salt and pepper.

In pan used for green beans, heat 1 TBSP butter (2 TBSP for 4 servings) and a large drizzle of oil over medium-high heat. Add coated chicken; cook until browned and cooked through, 5-7 minutes per side. 

Remove pan from heat. Transfer chicken to a cutting board. Let pan cool 2-3 minutes.

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

Stir in mayonnaise, stock concentrates, half the vinegar, remaining lemon zest, ½ cup reserved pasta cooking water (ladle straight from pot if pasta hasn’t finished cooking yet), and a squeeze of lemon juice (all the vinegar and 1 cup reserved pasta cooking water for 4). Bring to a boil, then reduce heat to low.

Return chicken to pan. Cook, flipping, until sauce has thickened and chicken is fully coated, 2-3 minutes. Transfer chicken to a cutting board.

Thinly slice chicken crosswise.

Divide pasta between plates. Top with chicken, remaining Parmesan, and remaining parsley. Serve with green beans on the side.