Cut the onion into quarters and the carrots into batons. Put in a large saucepan with the chicken, thyme, water and sherry (optional). Season generously with salt and pepper.

Bring to boil, then reduce heat and simmer for 15 minutes until the chicken is cooked through and tender when pierced with fork. Add more water during cooking if necessary. Drain, set the chicken and vegetables aside and reserve the stock.

Put the taliatelle into a saucepan of boiling salted water and cook according to the packet instructions until tender but still with slight bite.

Meanwhile, slice the mushrooms and crush the garlic. Melt the butter in a frying pan, add the mushrooms, garlic and fry for 5 minutes until softened.

Add the flour and cook for a minute. Gradually add the stock, stirring all the time, and cook until the sauce has thickened. Add the chicken and vegetables and heat through.

Drain the tagliatelle and divide between 4 serving plates. Put the chicken and mushroom mixture on top and serve sprinkled with parsley.