Method

Custard: make a sugar syrup by boiling sugar, water, lemon zest and cinnamon stick to 108°C/226°F (thread stage). In a separate pan, whisk flour into cold milk until smooth; heat gently stirring until it thickens to a very thick paste.
About 5 min
Beat egg yolks in a large bowl. Stream the hot sugar syrup into the yolks while whisking. Then add the flour-milk paste. Add vanilla. Whisk until smooth. Strain. Cool.
About 11 min
Pastry cases: roll puff pastry into a thin rectangle. Lightly dust with flour and roll tightly into a log from the short end. Cut into 12 equal rounds (about 1.5 cm thick).
About 11 min
Press each pastry round into a greased muffin tin cup with moistened thumbs, pressing from the centre outward to form a thin-walled cup with a slightly crimped edge.
About 11 min
Fill each pastry cup 3/4 full with the cooled custard.
About 11 min
Bake at the absolute maximum temperature of your oven — at least 250°C/480°F, ideally 270°C/520°F — for 12–15 minutes until the custard has dark caramel blisters and the pastry is golden. The dark spots are essential, not burnt. Dust with cinnamon and icing sugar. Eat warm.
About 3 min

Nutrition per serving (estimate)

Contains: gluten, dairy, eggs