Roast chicken and veggies: Preheat oven to 400℉. Place grape tomatoes, cauliflower, and carrots on one half of sheet pan. Drizzle veggies with 1 Tablespoon olive oil, sprinkle with 1 teaspoon Italian seasoning plus ⅛ teaspoon salt and ½ teaspoon pepper. Toss to coat and spread evenly. Place chicken in single layer on the other half of sheet pan. Drizzle chicken breasts with remaining 1 Tablespoon olive oil, 2 teaspoons Italian seasoning, ⅛ teaspoon salt, and ½ teaspoon pepper. Cook 20-30 min until chicken is 165℉ in center and veggies are tender.
While chicken is cooking, make barley, spinach, and heat sauce: Cook barley according to directions on package. Cook spinach: heat 8 Cups water and pinch salt to boiling in large pot. Add 1 package baby spinach. Cook three minutes. Heat 1 Tablespoon olive oil in sauté pan (can add sliced garlic for flavor if desired). Carefully strain spinach and add to sauté pan, season with ⅛ teaspoon salt and ½ teaspoon pepper. Cook 3 more minutes. Turn off heat and set aside. Sauce: When veggies and chicken are nearly done, gently heat sauce to warm in small saucepan or on low in microwave. Do not overheat sauce. If your pesto is particularly thick you can add a touch of olive oil.
To make bowls: Place ¼ barley in bottom of wide bowl or plate, add 1 piece of chicken, ¼ veggies, and ¼ spinach. Top with ¼ pesto sauce and then add ¼ of each topping. Repeat for remaining bowls.
Notes
While this goes together quickly, to make it even simpler you can do either of these steps the night before and store in fridge until you are ready to make your meal: Make barley and prep chicken and veggies.
When purchasing pesto, check ingredients for inflammatory oils. Pesto should use olive oil and not have any fillers. Alternatively, you can make your own.