A sauce of flour, melted butter, and milk or cream:fish in white sauce[count noun]:a simple white sauce...
Mix the cooked pasta, tomato, white sauce, salt and chilli sauce.
The book had no pictures, except on the cover, which showed a large roast of lamb, fish baked in white sauce accompanied by boiled carrots, and a mould of bright red gelatin.
Make a white sauce by melting the butter then mixing in the flour.