Combine first 3 ingredients sifting through a sieve into a bowl. Set aside.
In another bowl mix with a handheld mixer the butter until fluffy. Add both sugars and beat to a creamy consistency. Add egg yolk and incorporate. Then add dry ingreidents in 3 steps until dough holds together.
Quickly kned dough to a ball. Add more flour if dough is too moist.
Form into a ball and cut in 2. Form each into a disk and refrigerate for at least an hour.
Take disks out of refrigerator. Between to parchment papers roll out dough (ca 4 millimeters thick) and start cutting out cookies with a round cookie cutter.
Place cookies carefully on a cookie sheet layed out w/wax paper.
Sprinkle each cookie with chili salt and a little fleur de sel.
Bake in preheated oven (350 F) for 12 minutes rotating sheet after 6 minutes.