Preheat the oven at 250 degrees Celcius.
Lightly whisk together the cream and egg yolks in a bowl with a manual whisk.
Add the flour and sugar to the same bowl while mixing.
Add the mixture to a small saucepan, add the lemon peel and stir on medium heat until it boils.
As soon as bubbles appear in the center, immediately remove from heat and let it cool until just warm. Remove the lemon peel.
Cut 0.5-1cm thick pastry to coat the tart molds. Use your thumbs to pad out the pastry until it covers the interior - not too thick that it doesn't cook properly and not too thin that it has gaps.
Fill the coated molds with the egg mixture until each is about 90% full.
Put the tarts onto a baking tray lined with baking paper and then add them to the preheated oven. Bake for 10-12 minutes until the pastry is flaky and the custard has risen.
Allow to cool slightly. Dust with cinnamon and serve immediately.