filling: * 2 cups sliced rhubarb * 3 Red Delicious apples * 1/2 cup Sugar * 2 tablespoons grated lemon zest * 3 tablespoons golden raisins * 2 tablespoons tapioca pastry: * 12 sheets phyllo dough * 1/2 cup melted butter or shortening * 1/2 cup finely chopped walnuts