Brown two onions in a saucepan with one ounce of butter, stir in a little flour, and moisten with three pints of white broth (No. 99); season with half a tablespoonful of salt and a teaspoonful of pepper, and cook for ten minutes. Place six pieces of toasted bread in a bowl; cover them with fine slices of Swiss cheese, pour the broth over them, add a few more slices of cheese on top, and put it in the oven five minutes before serving.