Melt the butter in a large skillet. Add the mushrooms in an even layer, season with salt and pepper and cook over moderate heat until browned on the bottom, about 3 minutes. Stir the mushrooms and cook until tender, about 4 minutes longer. Add the shallot and cook, stirring, until lightly browned, about 3 minutes. Add the wine and cook until evaporated, about 30 seconds. Add the chicken stock and asparagus and simmer until the liquid has reduced to 2 tablespoons, about 2 minutes. Stir in the heavy cream and simmer over low heat until slightly thickened, about 5 minutes. Season with salt and pepper, stir in the parsley, chives and chervil, and serve at once.