In broad, heavy skillet over moderate heat, melt butter just until foaming. Add fresh porcini and chanterelle mushrooms, raise heat to high and sauté until butter is absorbed and mushrooms are hot. Add shiitake mushrooms and sauté until they begin to shrink, then add brown mushrooms and toss to combine. Add shallots and toss until all mushrooms release their juices. Add oyster mushrooms and diced dried mushrooms to pan. Toss to combine, reduce heat to medium and let mushrooms cook until liquid is reduced by half.
Combine sherry, soy sauce and stock, and add to pan. Cook while stirring, until most of liquid is evaporated. Add cream and stir until the mixture is thick and the cream lighlty coats mushrooms. Season with pepper to taste.
Spoon warm mushroom mixture into boxes. Garnish with a sprig of chervil or a sprinkling of parsley.