For the base, spread oil on a tart mould with a lifting base (24 cm Ø). Coarsely chop the chocolate coating and coconut oil and melt in a hot water bath. Put cornflakes and lady fingers in a large freezer bag and crumble finely with a rolling pin.
Mix well with the couverture and press into the mould as the base and rim. Chill for at least 1 hour.
For the cream, wash 2 lemons hot, dab dry and finely grate the peel. Squeeze all lemons and measure 150 ml of juice. Set aside 1 tablespoon of lemon juice. Separate the eggs, chill the egg white.
Bring condensed milk, cream, butter, 100 g sugar, 1⁄4 l water and the lemon peel to the boil while stirring in a saucepan. Stir 150 ml lemon juice and cornflour until smooth. Remove the pot from the stove and stir in the starch.
Bring everything to the boil again while stirring and simmer for about 1 minute. Whisk 6 egg yolks and stir in 1-2 tbsp. hot cream. Then stir the egg yolk mixture into the rest of the hot cream. Spread the lemon cream on the crumb base and smooth it down.
Allow to cool, then chill for about 2 hours.
For the meringue, beat the egg whites until stiff, adding 1 pinch of salt and 150 g sugar. Keep beating until the sugar is completely dissolved. Finally, stir in 1 tbsp. lemon juice.
Spread meringue loosely on the lemon cream and brown lightly with a kitchen gas burner. Serve immediately.