Method Melt butter in a shallow dish in microwave on full power, 30 seconds. Add pineapple pieces, onion, carrot, pepper and celery. Stir to combine and cook a further 4 minutes in microwave on full power. Blend cornflour, soy sauce and brown sugar with a small quantity of pineapple juice in bowl. Gradually add remaining juice, water, stock cubes and season with salt and pepper. Microwave on full power 5 minutes until bubbling. Add vegetables and chicken pieces to sauce and continue cooking in microwave on roast for 7 minutes. Serve with rice.