Wash the scallops well and cut into bite-size pieces if they are large.
Place the scallops and the wine in a skillet with a tight-fitting cover and simmer for about five minutes, or until tender. Drain and reserve the liquid.
Melt the butter and sauté the shallots and mushrooms in it for three to five minutes, until tender but not browned. Stir in the flour and gradually stir in the reserved liquid and the cream. Bring to a boil, stirring.
Add the scallops and parsley to the sauce and pour into a shallow casserole. Top with the bread crumbs and place under the broiler until the surface is lightly browned.