-
1
Combine the milk, sugar, lemon zest strips, and cinnamon stick in a wide, heavy saucepan. Set over medium heat and bring slowly to a gentle simmer, stirring to dissolve the sugar. The milk is ready when it is steaming, visibly trembling at the surface, and carries a clear scent of lemon and warm spice — it must not boil.
-
2
Add the broken vermicelli to the flavoured milk. Reduce the heat to low. Stir continuously with a wooden spoon, keeping the milk at a gentle simmer and attending closely — the milk foams and will boil over if neglected. Cook until the noodles are completely soft and the liquid has thickened appreciably around them; the spoon should leave a momentary parting in the mixture that closes slowly. This is where the dish lives or dies: under-cooked noodles will not set, and unattended milk will scorch.
-
3
Remove the pan from the heat. Discard the lemon zest and cinnamon stick. Working quickly, pour in the beaten egg yolks in a thin stream, stirring vigorously throughout. The residual heat of the noodle mixture is sufficient to cook the yolks gently; the mixture should thicken slightly and turn a deeper ivory. If any streaks of egg are visible, stir until they disappear.
-
4
Pour the mixture immediately into a shallow serving dish, spreading it level. Allow to cool to room temperature, then refrigerate until fully set and firm enough to hold a clean impression when lightly pressed with a fingertip.
-
5
Apply the ground cinnamon decoration through a stencil or fine sieve in geometric patterns directly onto the set surface, in the Portuguese confectionery tradition shared with arroz doce. Serve cold or at cool room temperature.