Whisking hot sugar syrup into the egg and milk mixture gives these custards a wonderfully smooth creamy texture. They are simply flavoured with lemon and make a delicious dessert served with shortbread biscuits.
Put the sugar and water in a heavy pan and heat gently until the sugar has dissolved.
Increase the heat and boil the sugar solution rapidly until it reaches 107°C/225°F on a sugar thermometer, or when a few drops added to a cup of cold water form a fine thread.