Salt and pepper or soy sauceOptional, see notes above and taste before adding
Instructions
Place the cornflour in a cold pan and stir in the cold stock. (If you need to make up your stock with hot water, add your cornflour to a little cold water first, and then stir it into the made up stock). Place over a medium heat and bring the stock up to a simmer, stirring occasionally
Meanwhile, beat the egg in a jug or small bowl until the white and yolk are mixed
Stir the simmering stock vigorously in one direction - you'll get a kind of whirlpool. Slowly pour in the beaten egg which will quickly set in ribbons. Turn off the heat and stir in the pesto. Taste and season if necessary.
Notes
The cornflour is optional - if you don't use it your soup will just be a little thinner.