Whisk 1/4 cup oil, lemon juice, rosemary, and garlic in small bowl. Season dressing with salt and pepper. Place potatoes in medium bowl; add 2 tablespoons dressing. Place turkey in another medium bowl; add 2 tablespoons dressing. Let potatoes and turkey marinate at room temperature 15 to 30 minutes, turning occasionally.
Prepare barbecue (medium-high heat). Brush grill rack with oil. Place potatoes and turkey cutlets on separate rimmed baking sheets; sprinkle with salt and pepper. Grill potatoes and turkey until charred and cooked through, 10 minutes per side for potatoes and 3 to 4 minutes per side for turkey. Divide turkey and potatoes among 4 plates. Drizzle with remaining dressing.
Per serving: 395 calories, 9 g fat, 3 g fiber Nutritional analysis provided by Bon Appétit