Preheat your oven to 200c/180c fan oven and roast your chicken breasts for 20 minutes until they are cooked through. Always check that your chicken is properly cooked!
Put your pasta in a pan of boiling water until cooked. It should take 10-15 minutes.
While your pasta is cooking, In a frying pan over a medium/high heat add the oil, onion, garlic and mushrooms and cook until the onions are softened and the mushrooms have a little colour.
Pour in the cream substitute then add your mustard, white wine vinegar and cornflour. Reduce the heat to low and leave to simmer for 5 minutes.
Add the parsley to the sauce and season to taste. Drain off the cooked pasta and then stir in a small amount of the sauce. Just enough to coat the pasta.
To serve put a chicken breast and half the pasta onto each plate and add a side salad if you want to. Then spoon half the sauce over the top of each chicken breast. Add a little more parsley to the top if you want to and enjoy!