- In a medium saucepan, mix sugar and cornstarch together. Stir in milk until well blended. Do not put the saucepan on heat.
- In a small bowl, whisk egg and yolk until slightly beaten then stir into the milk mixture in saucepan.
- Put the saucepan over medium heat and cook while stirring constantly until thick and bubbling.
- Remove from heat and stir in lemon peel, juice and butter.
- Pass through a strainer then spoon into individual serving bowls. Garnish with mint, lemon slices, blueberries, whipped cream, or anything you like.