Preheat oven to 350 degrees. Take about 1/4 cup flour and pound into the steaks, coating both sides.
Melt 4 tablespoons butter in skillet and brown steaks on each side, then place in an 8 x 11 inch baking dish. Melt 2 tablespoons butter, saute onions until tender, but not brown and spoon over steaks. Add 2 tablespoons more butter and saute mushrooms until tender and spoon over steaks and onions.
Add 2 tablespoons flour to butter remaining in skillet (if none is left, add 2 more tablespoons), stir in bouillon and mustard. Stir constantly until thickened. Stir in cream and pour sauce over steak. Cover with aluminum foil and bake for 1 1/2 hours. Serves 6.
Hints: Can prepare the dish the night before and refrigerate, then bake as needed. Goes well with rice and salad.
