Mix 3 eggs and 75 grams (or 2.6 ounces) of sugar in a bow.
Once the mixture turns white, add 20 grams (or 0.7 ounces) of corn starch.
Gently mix the batter
Boil 25 centiliters (or 1 cup) of milk with half of a vanilla pod or vanilla sugar.
Pour the boiling milk into the batter and mix.
Heat the batter on a low heat setting for one minute. Mix the batter to prevent it from burning or sticking to the pan. As soon as the cream becomes thick, it is done.
Pour the custard in a bowl, and then spread some butter on top to prevent the cream from hardening or forming a 'skin'.
And your confectioner's custard is done.