Mix the dry biscuits and mix them with the melted butter.
Using a glass or the back of a spoon, tamp this mixture onto the bottom and side of a 22 cm diameter springform pan lined with parchment paper. Refrigerate while waiting.
Cheesecake filling
Preheat the oven to 160 ° (traditional heat).
Whisk together the Philadelphia cream cheese and the ricotta. Gradually add (mixing between each) the powdered sugar, the flour, the zest of one lemon, the juice of 2 lemons.
In a bowl, relax the whole eggs and egg yolks with a fork, then incorporate them into the previous mixture.
Finally, add the crème fraîche. Beat one last time to obtain a very smooth mixture.
Pour the filling into the mold on the biscuit base and cook for 1 hour. If the cheesecake is still shaky, it is quite normal.
Let the cheesecake cool in the half-open oven, then refrigerate it for at least 3 hours (overnight is better).
lemon curd
In a saucepan, pour the butter, powdered sugar, the juice of 3 lemons, the zest of one lemon.
Separately, relax 3 whole eggs with a fork, and add them to the pan.
Heat over low heat without stopping stirring (do not stop, otherwise the cream will cook). The consistency obtained should be comparable to heavy cream.
Remove from heat and cool the pot in cold water to stop cooking.
Once the lemon curd has cooled, cover the top of the cheesecake and return to the refrigerator.
Crunchy meringues
Preheat the oven to 100 ° (traditional heat).
Whisk the egg whites until stiff with the pinch of salt. As soon as they start to foam, add the powdered sugar little by little.
Beat at maximum speed until you obtain a firm meringue (which forms peaks).
Then pour the meringue into a pastry bag fitted with a fluted tip, place the meringues on a baking sheet covered with baking paper and cook for 1 hour.
Let cool on a baking sheet, out of the oven.
Just before serving the cheesecake, place the small meringues on top (not too early, as the meringues will soften).
Notes
The cheesecake will be even better the next day (and the days following) it is made.Meringues should not be refrigerated otherwise they will become soft. It is best to place them on the cheesecake just before serving.