Slit the vanilla bean lengthwise, scrape out the pulp with a sharp kitchen knife and mix with the softest butter, sugar, salt and egg yolks.
Sift the flour over it, knead it into a smooth dough and let it rest in the refrigerator for 2 hours, wrapped in foil or parchment paper.
Cream the butter with the sifted powdered sugar and the eggs. Spoon in the almond kernels, lemon zest and flour. Roll out the short pastry. Line the bottom and sides of a springform pan with it. Spread the filling on the bottom and bake the cake on the second rack from the bottom for 45 minutes. Cool the cake in the form.
Other : Maybe even a night