Sift almond powder and flour.
Using the paddle attachment of your stand mixer, cream the butter. Add the sugar and salt. Mix. Add the egg and mix again. Scrape the sides of the bowl with a dough scraper.
Add the flour and almond powder in three times. Mix just enough to incorporate the ingredients. Stop right away as not to overmix the dough. Put your dough on a lightly floured work surface. Push out the dough with the palm of your hand and smear it over your work surface (it is called “fraiser” the dough).
Form a ball with the dough, slightly flatten it. Cover with plastic wrap and put in the fridge for a minimum of an hour.