Preheat the oven to 190°C / fan oven 170°C / Gas Mark 5.
Using a sharp knife, slice a pocket into each chicken breast and open it up. Spread one teaspoon of pesto sauce into each one, and share the Parmigiano Reggiano between them. Top with the basil leaves, then close the pockets and secure with cocktail sticks.
Spoon two tablespoons of the olive oil into a roasting pan and add all the vegetables, tossing them to coat. Season with a little salt and black pepper to taste. Arrange the chicken breasts on top. Sprinkle the remaining olive oil over them, and transfer to the oven. Roast for 25-30 minutes, until the chicken is cooked and the vegetables are tender. Serve at once.
Cook’s tip: Use red pesto sauce or sun-dried tomato puree as an alternative to green pesto.