Mustard Cream Chicken with Pasta

2 stalks celery, sliced
1 leek, sliced
500g chicken breasts, sliced
1/3 C dry white wine
1 T wholegrain mustard
200g low-fat natural yoghurt
2 t cornflour
1 t chicken stock powder
1/3 C water
300g pasta
Cook pasta. Spray frypan, heat and add celery and leek until soft, remove. Spray, cook chicken in batches. Add wine, mustard, yoghurt, and combined cornflour and stock and water. Stir until sauce thickens, add pasta, celery and leek, cook until heated through.