Step 1Spray a saucepan with oil and set over medium heat. Sauté the onion for 2–3 minutes. Then add the barley, stir for 1 minute. Add tomatoes and basil with 2 cups of water; cover and bring to the boil. Cook, stirring occasionally, for 15 minutes, or until most of the liquid has been absorbed. Add another cup of water to pan. Simmer, uncovered, stirring, for 10 minutes, until barley is tender.
Step 2Meanwhile, combine the olive oil, lemon juice and garlic in a shallow bowl. Season with cracked black pepper; add the chicken and turn to coat well.
Step 3Heat a non-stick frying pan or chargrill pan over medium-high heat. Cook the chicken fillets for 3–4 minutes, each side, or until cooked through. Remove from heat, cover loosely with foil and then rest for 5 minutes.
Step 4Stir the frozen peas, chopped asparagus, vinegar and half the parmesan through the barley. Cover and set aside for 5 minutes.
Step 5Slice the chicken. Top barley risotto with chicken and sprinkle with the remaining parmesan and extra basil leaves.