In a small saucepan, combine the milk, cinnamon stick, and lemon zest. Heat over medium heat until it begins to simmer. Remove from heat and let it infuse for 10–15 minutes.
Prepare the Custard Base:
In a bowl, whisk together egg yolks, 1/2 cup sugar, and cornstarch until smooth and pale.
Combine Milk and Eggs:
Slowly pour the warm milk into the egg mixture, whisking constantly to prevent curdling. Stir in the vanilla extract.
Cook the Custard:
Return the mixture to the saucepan and cook over low heat, stirring constantly until it thickens to a creamy consistency. Do not let it boil.
Chill the Custard:
Pour the custard into ramekins or shallow dishes. Let it cool to room temperature, then refrigerate for at least 2 hours until set.
Caramelize the Top:
Just before serving, sprinkle 1–2 teaspoons of sugar evenly over each custard. Use a kitchen torch to melt and caramelize the sugar until it forms a crisp, golden layer.
Serving and Storage Tips
