Heat broiler to high. Wash and dry produce.

Peel and mince garlic. Halve grapes. Halve ciabatta.

Place 2 TBSP butter (4 TBSP for 4 servings) in a small microwave-safe bowl; microwave until just softened, 10-15 seconds. Stir in half the garlic. Season with salt and pepper.

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

Heat a drizzle of olive oil in a large pan over medium-high heat. Add chicken; cook until browned and cooked through, 5-7 minutes per side.

Transfer to a cutting board.

Add remaining garlic to same pan over medium-high heat; cook until fragrant, 30 seconds.

Stir in stock concentrate and ¼ cup water (⅓ cup for 4 servings). Simmer until reduced, 2-3 minutes.

Stir in sour cream, half the mustard, and 1 TBSP plain butter (2 TBSP for 4); remove from heat. Season with salt and pepper. (Taste and add more mustard if desired.)

Meanwhile, in a large bowl, toss mixed greens, grapes, and walnuts with a large drizzle of olive oil and half the vinegar (all for 4 servings). Season with salt and pepper.

Spread cut sides of ciabatta with garlic butter; place, cut sides up, on a baking sheet. Broil until golden brown, 2-3 minutes. TIP: Watch carefully to avoid burning.

Halve garlic bread on a diagonal.

Thinly slice chicken crosswise.

Divide chicken, salad, and garlic bread between plates. Top chicken with pan sauce and serve.