Preheat oven to 450 degrees.
In a saucepan, sauté shallot and mushrooms in butter until soft, then add wine and sherry.
Heat until liquid is reduced to about 1/4 cup, then add cream and simmer until thickened, and set aside.
In an oven-safe skillet, sear breasts, skin side down, in oil over medium heat for 3-5 minutes.
Remove from heat and place in oven for 15-20 minutes, until golden brown.
Serve drizzled with chanterelle sauce.