ONION SAUCE

Peel the onions and drop them into plenty of boiling salted water, add the vinegar, and boil for a quarter of an hour. Drain and rinse them in clean warm water and chop them up. Melt the butter in a fireproof dish, stir in the flour, then gradually add the milk, and stir till they boil; add the sugar, onions, and a little salt and pepper; stir till boiling; rub the whole through a sieve, reheat, then add the cream and serve hot.