For the tart crust: In a mixing bowl, beat 1 egg with a fork. Add the salt and 1/2 cup sugar (100 grams). Mix with a wooden spatula until the mixture is foamy. Add all the flour at once and mix roughly with the spatula. Rub the dough between your fingers until it becomes crumbly. Add the butter in small pieces and knead the dough. The dough should no longer stick to your hands (if it does, add a little more flour).

Roll out the dough and press it into a floured and buttered tart pan.

Preheat your oven to 430°F (220°C). Peel and core the apples. Slice them thinly. No need to pre-cook the apples: arrange them directly on the dough, slightly overlapping. Set aside.

In a mixing bowl, beat the remaining 2 eggs. Add the rest of the sugar, then the almond flour and sour cream. Pour this mixture over the apples.

Bake in the preheated oven for 25 minutes. Remove from the pan and let cool.