• Using a sharp knife or kitchen shears, trim any fat from the chicken breasts, then use paper toweling to pat them dry.

  If necessary, use the flat side of a meat mallet to pound them to the an even thickness. Place the chicken in a gallon-sized Ziploc bag or a shallow glass baking dish.
• In a small bowl, whisk together the oil, vinegar, garlic, rosemary, and pepper. 
• Pour half of the marinade over the chicken, and set the other half aside to use as salad dressing.  Seal the bag or cover the dish with plastic wrap, and refrigerate it for 30 minutes to 1 hour.
• Meanwhile, preheat the oven to 400℉.
• Rinse the grapes, use paper toweling to pat them dry, then place them in a bowl. Drizzle oil and salt over the grapes, tossing them lightly to coat. 
• Arrange the grapes in a single layer on a parchment lined baking sheet.
• Cook in preheated oven for 12-14 minutes, using tongs to turn grapes over halfway through cook time. When the grapes are soft and bubbling, remove from the oven and allow them to cool on the pan slightly. 
• While grapes are roasting, heat 2 tablespoons olive oil in a large skillet over medium heat. Cook the chicken breasts for 4-5 minutes per side, or until cooked through to an internal temperature of 165℉.
• Remove the chicken from heat and set it on a cutting board. Cover lightly with foil and allow it to rest while you assemble the salad, then cut into thin slices or bite sized pieces.

Assemble the Salad

• Assemble the salad by dividing the spinach evenly into four bowls. 
• Top the spinach with crumbled cheese, walnuts, roasted grapes, and chicken. Drizzle each salad with dressing just before serving.