Heat six tablespoons of the olive oil in a frying pan over a medium heat.
Sprinkle some flour onto a plate. Coat the chicken thighs in the flour, shaking off any excess, and carefully place into the hot oil. Fry the chicken thighs for 4-5 minutes on each side, or until golden-brown on each side.
Remove the chicken thighs from the pan and set aside on a plate lined with kitchen paper.
Heat the remaining two tablespoons of olive oil in a frying pan and fry the onion, carrot, celery and mushrooms for five minutes, or until softened.
Add the wine and the stock, bring to a simmer and cook for a further 10 minutes.
Return the chicken to the pan and season to taste with salt, freshly ground black pepper and nutmeg. Continue to simmer for another 4-5 minutes, or until the chicken is cooked through
Just before serving, stir in the egg yolk mixture until smooth and sprinkle over the parsley.