How to make
Cut the cold butter into small cubes. Put it in a blender or food processor with the flour and sugar and beat. Add water spoon by spoon, constantly stirring.
Take out the resulting dough and shape it by hand. Make it into a ball and store it for 30-40 minutes in the refrigerator, wrapped in foil. Spread a piece of foil on the counter and roll out the dough on it.
Using this foil, transfer the dough into a greased form, it needs to cover the walls. Lightly press and form the crust.
Pierce it lightly with a fork all over and put it to bake for 15-20 minutes in a 390°F (200 °C) oven. For the lemon cream, put the lemon juice, lemon rind, sugar, butter and water to boil in a pot on the stove.
Beat the yolks with the flour and starch separately and while stirring continuously, add them to the hot mixture. Stir and simmer for 2 minutes on the stove to thicken.
Once you remove them from the heat, stir in 2-3 tablespoons of mascarpone. Beat the egg whites into a hard snowy substance with a few drops of lemon juice and add the sugar and essence.
Pour the lemon cream over the baked pie, smooth the top out with the egg whites. Bake at 360°F (180 °C) for 15 minutes.
Optionally, you can replace the meringue mixture with whipped confectionery cream, but do not bake in that case.