German Soup

Take one carrot, a turnip, a head of celery, parsnip, an onion, or the white parts of spring onions, and either cut or scoop all these into very small squares or olive shapes; put them into a stewpan with a piece of butter, a spoonful of sugar, and a little pepper and salt, and fry them lightly over a slow fire; then add two lettuces and a little tarragon and chervil shred coarsely; stir these again over the fire for a few minutes, and mix in two ounces of flour ; moisten with three pints of good white stock, boil gently for half an hour, incorporate a leason of four yolks, and half a pint of cream, without boiling; ascertain that the seasoning is correct, and serve.