Boil the milk with 100 g sugar, the finely grated zircon peel and the cinnamon stick. In the meantime, mix the egg yolks, cornstarch and 1 tablespoon of milk with the whisk of a mixer. When the milk boils, remove the saucepan briefly from the stove, remove the cinnamon stick, and whisk in the egg yolk mixture. Return the saucepan to the kitchen stove repeatedly and heat, whisking throughout, until the mixture begins to set. Pour into small ramekins and cool. Empty the remaining sugar into an ovenproof dish and caramelize in a heated oven on high. Coat the surface of the crem as thinly as possible with it (drizzle in a spiral pattern). The caramel will harden as it cools.