Blend the icing sugar and egg yolks to form a soft, smooth mixture. Sieve in the corn starch and stir constantly with a wooden spoon to avoid lumps. When the mixture is soft and smooth, gradually pour in the cold milk, stirring constantly. Add the piece of lemon rind (or more than one piece if you want to add extra flavor). Bring to the boil on a low heat and stir constantly. When the mixture comes to the boil, reduce the heat and leave to cook. You can adjust the thickness of the custard by increasing the boiling time (minimum time 2 minutes and maximum time 4-5 minutes). Pour the custard into small flute glasses while it is still warm, and leave to cool for an hour. Complete the preparation by decorating the desserts with 3 or 4 Amarenas and a bit of syrup. Serve cold.
Recipe by SIMONA