Cook two pounds of Brussels sprouts in boiling water. Take them out, drain them and toss them in butter for five minutes, sprinkle them with a teaspoonful of flour, and then cook them in gravy (or meat extract and water), fast boiling, over a good fire, and keep the lid of the saucepan off so that they may remain green. Pass them through the sieve, leave them in ten minutes, bind the mixture with the yolks of three eggs, a pint of milk; then at the last minute one dessert-spoonful of butter for each pint and a half of soup.