Cognac Sauce

Melt the butter in a heavy medium-size saucepan over medium heat. Add the shallots and garlic and saute until transparent, about 3 to 4 minutes. Then add the cognac and flame. To do this, remove the saucepan from the heat and touch a lighted match to the edge of the pan; the fumes of the cognac will ignite. Holding the pan away from you, allow the flames to die down naturally. Add the stock and cream and simmer over low heat until thickened, about 15 to 20 minutes. Add the mushrooms and continue to simmer 3 to 5 minutes more. Season with