2 Tbs dried porcini mushrooms (soak in boiling water for 30min)
50ml Madeira wine or sherry
500ml chicken or vegetable stock
1 Tbs chopped fresh sage
Heat a pan with the extra virgin olive oil, lightly salt the chicken breasts and add them to the pan, browning them on both sides and then remove them.
In the same pan add the onion, button mushrooms, pinch of salt & pepper and cook that down until the mushrooms collapse.
Remove the now soft mushrooms and roughly dice them, then add to the other mushrooms and continue cooking.
Splash in the Madeira or Sherry and let that evaporate then add the stock so that there is enough liquid. Nestle the chicken back in amongst stock and mushrooms and simmer very gently with the lid on till the chicken is cooked (about 15 minutes)
Remove the chicken and put it aside and keep it covered and warm on a plate. Add the sage and some more black pepper and reduce the liquid on high heat until you get to sauce consistency. Then if you wish add a little of the water that the porcini mushrooms were soaking in just to bring consistency up. Whisk through the butter and cook down till sauce consistency again. (The addition of cream is for personal preference if you wish.)
Slice the chicken and serve the sauce over the chicken.