Melt 1 tbl of butter in the top of a double boiler. Add the wine and heat, then stir in 2 cups of the cheese. Heat until melted. Add a little of the cheese mixture to the beaten egg and then add the egg mixture back into the cheese. Cook and stir about 1 minute. Add the Worcestershire sauce and basil, set aside keeping the sauce warm. Saute the mushrooms in the remaining butter until just tender then sprinkle with the garlic powder and remove from the heat. Arrange toast points or triangles on individual heatproof plates. Spoon the sauce over the toast then top with the sauteed mushrooms. Sprinkle with the remaining cheese and broil until bubbly.