Pastéis de Nata

Combine the milk, lemon zest, and cinnamon stick in a saucepan. Heat over medium until just simmering, then remove from heat and let steep for ten minutes. Remove the lemon zest and cinnamon stick. This infusion gives the custard its signature flavour.

In a separate saucepan, combine the sugar with a third cup of water. Cook over medium-high heat without stirring until the syrup reaches 100C on a candy thermometer, about five minutes. This creates a clear, hot sugar syrup for enriching the custard.

Whisk the egg yolks in a bowl. Slowly pour the hot infused milk into the yolks while whisking constantly. Stir in the cornstarch slurry and vanilla. Then pour the hot sugar syrup in a thin stream into the egg mixture, whisking vigorously throughout.

Strain the custard through a fine-mesh sieve into a jug. Let cool to room temperature. The custard should be thin and pourable, much thinner than you might expect. It thickens during baking to achieve the perfect wobbly, creamy set.

Roll the puff pastry into a tight log and slice into twelve rounds. Press each round into the well of a greased muffin tin, pushing the dough up the sides with your thumbs to create thin, even shells with the spiral pattern visible on the bottom.

Pour the cooled custard into each pastry shell, filling to about two-thirds full. Do not overfill as the custard puffs during baking. Bake at 250C (the highest your oven goes) for twelve to fifteen minutes until the pastry is deeply caramelized and the custard has charred spots.

Remove and cool in the tin for five minutes, then transfer to a wire rack. The charred, blistered tops are the hallmark of authentic pasteis de nata. Dust with cinnamon and serve warm. These egg custard tarts from Belem are Portugal's most famous pastry.