Pre-heat the oven to 220 ºC / 430 ºF.
Separate egg whites from the yolks and pass the yolks through a sieve.
In a medium pan, mix flour, sugar, and cinnamon. Add the cream and yolks, mix till well blended and then add the lemon peel without the white part.
Heat this mixture over medium heat, stirring once in a while until it gains consistency. Once the cream mixture is thicker stir continuously. When lifting the spoon you're able to draw, with the cream that falls off, and the drawing doesn't disappear, it's ready.
It took me 30 mins total, using an induction plate, intensity 6 from 9 (maximum power).
Remove from the heat and transfer to another container covered with plastic wrap. Let it cool to room temperature.
When the pastry is at room temperature, roll it to 3 mm approximately. Put it over the tart pan and cut off the excess with a very sharp knife.
Place a sheet of parchment paper over the pastry, making sure that the edges are covered.
Fill the cavity with beans and bake for 12 to 15 minutes.
Remove from the oven and, carefully, take out the beans to a container to cool with help from the parchment paper, so you can save it and reuse it later.
Place the pastry again in the oven for more 5 minutes, without any protection.
Remove and let it cool on a wire rack.
Increase the oven temperature to maximum (250 ºC, 482 ºF electric/ 260 ºC, 500 ºF gas) and let it warm up for at least 30 minutes. If it beeps, indicating it's ready, it isn't.
With both pastry and filling at room temperature, pour the filling over the pastry and smooth the top.
Fold the long side of an aluminum foil sheet in half and cut a half moon in the center. This way, when you open the sheet of aluminum foil and put it on top of the tart, the pastry is covered but not the filling.
Bake for 5 minutes on the top shelf of the oven, being careful so it doesn't burn.
Then, place it on the bottom shelf, or on the bottom of the oven, for another 5 minutes, being careful so the base of the tart doesn't burn.
Remove and let it cool on a wire rack. When you're able to pick up the pan without burning your hands, unmold and treat yourself. Let it cool completely, if you want a more firm filling or if you can resist =).
*It's imperative that the oven is hot, otherwise the top of the filling won't have that beautiful color and the puff pastry won't be crispy and flaky.
*If for any reason your oven is cold when you'll bake the tart, the pre-heating time will be between 40 and 60 minutes.
*The filling can be made up to 3 days in advance and kept in the fridge, covered with plastic wrap.
*The crispness will be gone in one day or two. If you can resist for that long! =)