Spread whole almonds across baking paper lined pan and toast in the oven at 350 °F. Watch carefully so almonds don’t burn, toasting time is about 20 minutes. Set aside and let cool completely.
Grind the almonds, set aside.
Shortcrust Dough
In a large mixing bowl stir together flour, sugar and salt.
Add cubed cold butter, toss together until coated with flour mixture.
Use pastry blender to cut the butter in until the mixture resembles a coarse meal.
Add an egg and use wooden spoon to mix and hydrate the mixture. Mix until you obtain a coarse granular structure without loose flour left in the bowl.
Use your hands to quickly press together dough pieces just until they come together. Don’t knead, we just want a rough dough that is held together in one piece!
Transfer the dough on a kling wrap lined counter. Wrap the dough and roll over the kling wrap with rolling pin to create a disk.
Refrigerate the dough for 30 minutes.
Butter the tart pan.
Line the counter with overlapping sheets of kling wrap film to create large enough surface to roll out about 33 cm (13″) dough round on top of it.
Take the dough out of the fridge, unwrap and slowly roll out with rolling pin into thin, round with diameter of about 35 cm (14″).
Turn upside down by placing the center of stretch dough into center of tart pan. Carefully and lightly press around the pan perimeter to make tight fit between the dough and the pan bottom/side.
Carefully peel off the kling wrap.
Use the roling pin to roll across the top of the tart pan to cut off excess dough that is overhanging the pan edges.
Cover the tart pan with kling wrap and place in the fridge while you are making a filling.
Filling
Preheat the oven to 170°C (338°F), rack in the middle.
Add sugar, salt and eggs, to a stand mixer bowl. Mix at medium high speed for 10-15 minutes or until the egg mixture is light color and well fluffed up.
Mix in lemon zest, ground cinnamon, melted and cooled butter.
Using rubber spatula or whisk incorporate toasted ground almonds into the mixture. Do it in 2-3 batches and in few short and sweeping strokes in order to integrate ground almonds but avoid deflating the egg mixture.
Assembly
Use a fork to prick the dough bottom in the tart pan.
Pour the filling into the dough mold and bake for 40-45 minutes.
Take the torte out of oven, leave it in the tart pan and let it cool completely on a cooling rack.
Once completely cooled carefully unmold the cake, place on a serving dish and dust with confectionary sugar.