For the lemon filling

1. Place lemon juice, zest, sugar, eggs, egg yolks and salt into a medium heatproof bowl set over a small saucepan filled with an inch of simmering water.  Whisk constantly until the mixture thickens, about 10 minutes.  The temperature should read 170°F/75°C and the mixture should coat the back of a wooden spoon.
2. Pour through a fine sieve into a blender.  Allow to cool for about 15 minutes (the temperature should be approximately 140°F/60°C).
3. Blend the butter into the lemon mixture, a couple of pieces at a time.  Once all the butter has been added and incorporated, pour the lemon filling into a container.  Place a sheet of plastic wrap directly onto the surface of the filling to prevent a ‘skin’ from forming.  Refrigerate for at least 4 hours.

For the pâté sucrée

1. In a stand mixer fitted with the paddle attachment, cream the butter and salt on medium speed for 1 minute.  Scrape down the sides and bottom of the bowl and add the powdered sugar.  Beat on low until combined.
2. Add the almond flour and vanilla and continue to mix on low speed until just combined.
3. Slowly add the eggs and about one-quarter of the cake flour while on low speed.  Allow to mix until just incorporated.  Scrape down the bowl.
4. Slowly add the remaining flour and mix just until the dough comes together.  Do not over-mix!  The dough should be soft to the touch and not sticky.
5. Turn the dough onto a piece of plastic wrap.  Press into a 1/2-inch thick rectangular block and wrap tightly.  Refrigerate for at least 2 hours or overnight.
6. Remove the dough from the refrigerator and cut into 6 equal sized pieces and roll each piece of dough until about 3 mm thick.  Line six 4-inch (10cm) tart pans or tart rings and trim off any excess dough.  Place onto a parchment line baking sheet pan.  Using a fork, gently perforate the bottom of the shells.  Refrigerate uncovered for at least 1 hour.
7. Preheat oven to 325°F/163°C with the rack positioned in the middle of the oven.  Line your tart shells with parchment paper and pie weights, dried beans, or rice (to blind-bake).
8. Bake your tart shell in your preheated oven for 15 minutes.  Remove the filling and return you tart shells to the oven for an additional 15-18 minutes or until light golden brown.
9. Allow to cool to room temperature.

To assemble

1. Fill the tart shells with the lemon filling.  Refrigerate for 30 minutes before serving to set.