Chicken and chestnut mushroom pasta bake

1. Preheat oven to 200°C/fan 180°C/gas mark 6. Lightly grease an ovenproof dish; set aside. Cook macaroni according to packet instructions. Drain and set aside.
2. Place leek, courgette, mushrooms and stock in a non-stick saucepan; stir. Cover; cook over a medium heat for about 8 minutes or until vegetables soften, stirring occasionally. Remove from heat; drain off excess liquid. Set aside.
3. Rinse vegetable pan; use it to make cheese sauce. In a bowl, mix cornflour with a little milk until smooth. Pour remaining milk into pan; stir in cornflour mixture. Bring to boil over a medium heat, stirring until thick and smooth. Simmer for 2 minutes, still stirring.
4. Remove the pan from heat; stir in 55g (2oz) of cheese, mustard, parsley and black pepper to taste. Stir in chicken, cooked macaroni and cooked vegetables.
5. Transfer mixture to prepared dish; top with tomato slices. Mix together breadcrumbs and remaining cheese; sprinkle over mixture. Bake in oven for 20-25 minutes or until hot.

Cook's tips

• Using wholewheat penne instead of macaroni will make this dish healthier and more filling by increasing its fibre content.