MUSHROOM AND ONION GRATINS
1 pound mushrooms, sliced thin
1/2 stick (1/4 cup) unsalted butter
1/4 cup all-purpose flour
2 large onions (about 1 3/4 pounds), sliced very thin
6 tablespoons heavy cream
1 cup grated Gruyere
1/4 cup fresh fine bread crumbs
In a skillet cook the mushrooms in 2 1/2 tablespoons of the butter
over moderately low heat, stirring, until they are softened and
most of the liquid they give off has evaporated. Stir in the flour
and cook the mixture, stirring, for 3 minutes.
In each of six 1 1/2-cup gratin dishes layer the onions, the
remaining butter, cut into bits, the mushroom mixture, and salt
and pepper to taste, beginning and ending with a layer of onions,
and pour 1 tablespoon of the cream over the top of each gratin. In
a small bowl combine well the Gruyere and the bread crumbs and
sprinkle the mixture over the cream. (Alternatively, the gratin,
layered in the same manner, may be prepared in one 2-quart gratin
dish.) Bake the gratins in the middle of a preheated 325 deg. F.
oven for 50 minutes to 1 hour, or until the onions are tender and
the tops are golden. The gratins may be prepared 3 hours in advance,
kept covered and chilled, and reheated in a preheated 400 deg. F.
oven for 5 minutes, or until they are heated through. Serves 6.